Oyster Reef Ecosystem Tank

[Michael Hoaster]

Marine Depot sells a Tunze regulator for $110. If I was shopping for one, I'd get the tunze. They're products will outlive mankind. Those Germans know a thing or two.

I'm very excited to hear you are going this route! Please document your experience here for others to see. CO2 is easy!

[McPuff]

Originally Posted by Michael Hoaster

Marine Depot sells a Tunze regulator for $110. If I was shopping for one, I'd get the tunze. They're products will outlive mankind. Those Germans know a thing or two.

I'm very excited to hear you are going this route! Please document your experience here for others to see. CO2 is easy!

The Tunze regulator is pretty good. I had one that seemed to do well, but I had an issue with the needle valve so I had to ditch it. It was a returned item so it may have been defective from the start. I'd say give them a try. I love Tunze products.

[Chasmodes]

Thanks Michael and McPuff!

[Chasmodes]

I have some updates on my 20g long. The Ulva is pretty much gone. I'm not sure that the parameters are right from growing macros in this tank (light, etc.), plus, I'm sure that the shrimp and crabs eat some of it. I probably won't add much until I get the main tank set up. I can't tell of the other macro is growing or not. There are some parts that seem to, and others I'm not so sure about. It looks good in the tank still, and provides good cover for the smaller fish, so I'm leaving it in there. The sea grasses have died off, so that experiment ends until I get the main tank set up. I have some cyanobacteria and some green hair algae areas on shells and sand where the most light hits that could be competing with the macros and seagrass for nutrients. Right now, I'm not too worried about this but would like to figure it out prior to setup of the main tank. We will see how that goes. I personally don't think it looks that bad as it still adds color, plus, the crabs and shrimp seem to eat it.

Both colonies of bryozoans are expanding across the tank glass on either end of my tank, in the darker areas. They look cool.

One thing that came in handy was the purchase of an automatic feeder to keep my fish fed while I was away on vacation. We couldn't find anyone reliable that new much about fishkeeping, so this was my solution. It worked out OK. The only issue that I anticipated was if the fish would actually adapt to and eat flake food or pellets, since, up until my trip, all they've eaten were live or frozen foods for the most part. My attempts at feeding them flakes were with mixed results. The gobies ate flakes with gusto. Some of the blennies ate the flakes, ingesting some or spitting out some, and other blennies ignored the flakes. The skilletfish ate flakes at times, but not often.

As far as pellets go, they were a little too big for most of my fish, and for the ones that tried to eat them, they spit them out at first and later kept attacking them until they were bite sized enough to eat them. The blennies broke them up and ate some, and then the gobies would follow behind and eat some of the fragments, while the skilletfish ignored the pellets altogether.

So, I made the decision to go with flakes in the auto feeder. I had no other choice.

After returning from my trip, I noticed that all of the fish will eat flakes now. Gobies still eat them with gusto, as do the blennies if they're hungry. If the blennies aren't hungry, they ingest them and sometimes eat some of the "flavors" while spitting out others. Skilletfish will eat flakes at times, but not that much.

The gobies and blennies all grew and are all fatter than fat. A couple of the gobies grew almost a 1/2" while we were gone (about 10 days), which I thought was amazing.

Also, I thought that I had only two crabs in the tank, but as it turns out, there are three of them. I've identified two of the crabs as the white-clawed mud crab, a.k.a. the Harris mud crab (Rhithropanopeus harrisii). I'm not sure of the third crab species as it looks different, but, I really haven't had a good look at them. Until now, the crabs have been hiding mostly. Recently, two of them come out during feeding time, and one of those is out foraging even while not feeding. In fact, last night, it was moving all over one of the oyster reef structures all the way to the water's surface.

From what I've read, they only grow to about an inch or so, and they aren't aggressive toward fish or shrimps. I'd bet they'd eat them if they could catch them, but, so far, I've seen blennies actually land on them and the crabs just move away. They raise their claws if fish near them, but so far, haven't tried to grab any fish. The shrimp seem to be good at avoiding them. I also read that these crabs feast on all types of snails. I don't have snails in my tank at the moment, but if I add them, these will have to be stocked often to keep a population of them.

Here are a couple videos of my tank.

The first one pretty much follows the largest blenny of the tank:
https://youtu.be/mBe7XgwgZ-M

I tried to view the tank in general with this video, bouncing from one fish to another:
https://youtu.be/dc_YRaTyF0s

Hope you all like them.

[Michael Hoaster]

Thanks for the update fix. I'm really enjoying it! The vids are great.

It's fascinating, hearing of your experience with this type of tank. I'm sure you're inspiring people!

I do agree it would be helpful to work out some issues in these 'pre-tanks'. I'm guessing you'll need to shift your focus towards plants a bit, to insure you can have the success you want with them, and they become a critical part in your tank's ecosystem.

In the meantime, I'm enjoying following your journey!

[Chasmodes]

Thanks Michael.

I just wanted to say that I haven't given up on growing macros in these 20g tanks, just the grasses for now. I think that if I can successfully grow the Ulva and other macros, then that would be a good start for the grasses when I know that my lighting is adequate. I simply don't want to spend a ton of money on these smaller tanks.

I won't add Ulva to the 20g long since it dies off. But, I still have some that seems to be doing better in the 20g high tank. I have been using a simple reflector and an LED Home Depot bulb, and have since added another of the same fixture and bulb. The other algae seems OK too. There may be some die off, but also more signs of growth (the Ulva is still very vibrant green after 2 weeks and the only die off is in a dark corner of the tank), and little to no cyanobacteria in that tank, and the bioload consists of a bunch of grass shrimp, a few mud crabs, and one skilletfish. That is encouraging to me.

As far as the 20g long tank goes, I'll try manually removing some of the cyano and see if that reduces the competition.

In the main tank, the key will be the set up and planning, making sure that the substrate is optimal, that there will be enough nutrients (including the purchase of the CO2 regulator) and sufficient bioload, and finally that I introduce more macros early to eliminate competition. The substrate for the main tank will be seeded by substrate from these tanks. And the lighting should be perfect for good plant growth. By the time that I think that raising the SG to a higher level might also help in the long run.

One thing that I need to figure out is a better way to mount the macros than just tossing them in and weighing them down, or at least find a better way to weigh them down, LOL. I hope to do more collecting soon, hopefully to get some amphipods and maybe a few more fish for the 20g high. The lone skilletfish is a huge one, about 2.75" long and a head about an inch across. It is fatter than I'd expect, so I'm wondering if it is an egg bearing mature female. I'd like to get a couple more skilletfish at about the same size to see if I can get them to breed. Plus, that tank needs more activity and the additional bioload should help with the macroalgae growth. That tank had about 25 fish in it a few weeks ago before a gave them away. The big skilletfish was a new addition afterwards.

[Chasmodes]

Here is a video of one of my crabs. I think that this crab is the white-clawed mud crab, a.k.a. the Harris mud crab (Rhithropanopeus harrisii). If this is not correct, I'd appreciate the correct ID. (thanks in advance)

https://youtu.be/EWN32SSwcAw

[Chasmodes]

We discovered a new critter in my 20g long tank. After feeding some frozen brine shrimp, my daughter noticed a worm-like creature, a little over an inch long, swimming around the glass in the front right corner of the tank, about mid depth. At first, I thought it was a chunk of dead sea grass caught in a current eddy, but nope... Upon closer inspection, it was brownish and had a segmented body, with 2 long antennae or head appendages, and a bunch of legs. It resembled a centipede, so I assumed it was some sort of isopod. It was too fast to get a picture. By the time that I had my phone at the ready, it had scurried back into the oyster reef. It was pretty cool.

Of course, I had some concern about the potential for parasitism, even though I thought it was probably OK (because if it was a fish parasite, then it would have a host by now especially since it was over an inch long). Anyway, I thought it was pretty cool but it freaked the heck out of my daughter.

After researching on-line, it looks a lot like the on-line pictures of the elongated eelgrass isopod, Erichsonella attenuata. This species, if correctly ID'd, is not a threat for parasitic activity.

I will try and get pics and see if anyone can confirm the ID.

[Chasmodes]

I have an update for my oyster reef "system". The 20g long that started this thread is still going strong, with 6 small striped blennies, 5 small skilletfish, 5 naked gobies, two new juvenile killifish (probably juvenile mummichogs), 3 white-clawed mud crabs, an unidentified harmless isopod, a bunch of grass shrimp, and red macroalgae. All of the fish are fat and healthy. I tried to add three silversides but that didn't work out. They made it home just fine, which is what worried me the most. They were about 2 1/2" long and looked great in the tank, until the 2" clingfish killed and ate the first one. Another one was harrassed by the blennies and died, then devoured by the gobies and a crab. And the last one died of unknown causes during the night, probably killed by the same culprits. The only issue with the tank is that with the heavy bioload and feeding, cyanobacteria growing some pretty large patches. I don't think it looks necessarily bad, but I'd rather have those nutrients consumed by Ulva which hasn't done well in this tank.

The 20g high tank that I was using as a holding tank is now set up as a display also. I added a large artificial oyster cultch that I built for my large tank so that it could also grow life and additional bacteria needed to cycle my large tank when I set it up, in addition to the sand. This tank seems to grow Ulva pretty well. I have a small hang on back power filter and a bubble sponge filter in the tank, and two garage clamp on light fixtures overhead with LED bulbs. Cheap and simple, but it works. Over the weekend, my daughter and I went collecting again and found some inhabitants for this tank. We added 6 adult blennies, 2 jumbo skilletfish, 5 adult naked gobies, and two mummichogs to the tank. We had one jumbo skilletfish, a live barnacle, a bunch of grass shrimp, and 3 mud crabs in the tank prior to adding these. When rearranging the tank and moving the oyster shells around, I discovered that bloodworms were living in the tank. Awesome! A natural food supply! I also discovered a tunicate that is alive and well, and is growing much faster than I thought that they would. I think that the Ulva is really responding to the heavy bioload. I have a little bit of cyano in the tank and some hair algae, but the macros (Ulva and a red algae) are doing well. The fish have only been in the tank for a few days and are already feeding out of my daughter's hand. All of the fish were eating mysis shrimp the night that we introduced them to the tank. All are fat and healthy.

Here's a video of the blennies in the 20g high (sorry about the music, I figured it was better than hearing our clothes dryer running):
https://youtu.be/hn8xIsLFZ_8

The water parameters of both tanks are great. No ammonia, no nitrites and very little nitrate, so the bacteria and algae are doing their job.

[Michael Hoaster]

Great update and vid!

[Chasmodes]

Thank you Michael!

Feeding the 20g high some frozen chopped clams. It's like a fish mosh pit...

https://www.youtube.com/watch?v=sVJM6R5Y0Yk&t=129s

[McPuff]

Hey in case you're still looking for the CO2 regulator... I just got an email from CO2art saying they're back up online! So check them out! Like I said, I could not be happier with the dual stage regulator I purchased from them.

[Chasmodes]

Originally Posted by McPuff

Hey in case you're still looking for the CO2 regulator... I just got an email from CO2art saying they're back up online! So check them out! Like I said, I could not be happier with the dual stage regulator I purchased from them.

Thanks McPuff! I'll check them out.

[Michael Hoaster]

Also, if you are interested, I saw a DIY regulator thread in the DIY section.

[Chasmodes]

Thank you Michael.

Quick update: the Ulva in the 20g high is doing well. No die off now and seems to be growing. One thing that I noticed that when it dies off, the large "leaves" tend to break apart and get holes in it. That isn't happening in this tank. I'm not sure about the other algae, but it's hanging on. These fish are all tame, almost too tame, because they don't act naturally, always coming to the front for food, even with full bellies after a meal. If I stay still, they kind of forget that I'm there after a while, but if I move or flinch, they come back and chase the glass again. I guess I'll need to build a blind if I want to see them act naturally. What gluttons! But, the good news is that all of the fish are healthy.

The tunicate is doing well and the barnacle is still alive. I haven't seen any crabs, but I know that three are in there. It is possible that the fish ate them. I guess I'll have to visit the tank at night and view with a red light so I can see what else lives in there that the blennies haven't eaten.

Here's another feeding video, featuring mostly skilletfish feeding out of my daughter's hand with the others hanging around for dropping morsals.

https://youtu.be/00z25IgiJEQ

[Subsea]

Originally Posted by Chasmodes

One of my dreams was to duplicate the oyster reef environment of the Chesapeake Bay as best I can without predation. My plan is to have a 120g corner quarter cylinder tank with a live sand from the Chesapeake Bay and perhaps some of the rock there for the live rock. I'll purchase some porous base rock and take my time getting the bio filtration going. I'll have a refugium/sump too, probably 55g.

Animals will be collected from the Bay that live side by side in this environment:

Chasmodes Bosquianus - striped blenny

Hysoblennius hentzi - feather blenny

Naked goby

Skilletfish

Northern pipefish

Ghost shrimp, hermit crabs, snails, etc. for clean up crew that live in the bay.

just about any critter that comes in on the rocks (fish will not be introduced for 6 weeks after the tank cycles and they are QT'd to reduce parasitism).

I may try my luck at some of the other species of fish too eventually.


The actual reef will be an oyster reef but I'm not sure if that will include live oysters or not. I was thinking that if live oysters would be the best way to go to perhaps separate them from the fish in the fuge...my concern is that if one of them dies that I'll have pollution and kill the fish. So really I'm leaning on just using empty dead oyster shells and maybe have one or two oysters in the tank that I can monitor.

The Chesapeake bay is brackish and the salinity varies based on rainfall and runoff, but these fish have bred in captivity with a salinity of 1.015 or so. Also, the environment is colder and there are no coral growth issues.

Has anyone done this? What do you think? The blennies will be my main focus.

I really like your focus on this tank. When I first set up a marine tank in 1971, I used water on an incoming tide. Crushed up oyster shells from a chicken feed supply house was my substrate. I used an oyster cluster rock with numerous filter feeders. From the Galveston jetties, I collected Peppermint Shrimp and anemonies. I recall one fish store that had Curly Cue Anemonies that were brillianly colored. I asked the store owner where the colorful anemonies came from. When I told him that the ones I collected were translucent in color, He told me to get some food dye and a syringe. I inquired as to how long this treatment worked, he said about 30 days, then his customers would come buy more. Needless to say, it was the last time I visited that store.

[Michael Hoaster]

You mean you DON'T have a duck blind for viewing your tank? Doesn't everyone? Ha! Who knew those little guys were so smart! Can you darken the room lighting? You are the hand that feeds them. The feeder should help. I feed with a turkey baster. My fish perk up when they see it...

[Chasmodes]

Originally Posted by Subsea

I really like your focus on this tank. When I first set up a marine tank in 1971, I used water on an incoming tide. Crushed up oyster shells from a chicken feed supply house was my substrate. I used an oyster cluster rock with numerous filter feeders. From the Galveston jetties, I collected Peppermint Shrimp and anemonies. I recall one fish store that had Curly Cue Anemonies that were brillianly colored. I asked the store owner where the colorful anemonies came from. When I told him that the ones I collected were translucent in color, He told me to get some food dye and a syringe. I inquired as to how long this treatment worked, he said about 30 days, then his customers would come buy more. Needless to say, it was the last time I visited that store.

Thank you Subsea. I bet that was a very cool tank!

I guess shady characters exist in every business. It's up to us to learn and become knowledgeable so we can sort out the best retailers from the crooks. I bet that guy now does robocalls selling anemone warranties.

[Chasmodes]

Originally Posted by Michael Hoaster

You mean you DON'T have a duck blind for viewing your tank? Doesn't everyone? Ha! Who knew those little guys were so smart! Can you darken the room lighting? You are the hand that feeds them. The feeder should help. I feed with a turkey baster. My fish perk up when they see it...

Ha!!! My daughter gets a kick out of feeding them, so the 20g high might stay her tank. I'll just have to collect more blennies for the big tank and find a way to feed them without them associating me with food (maybe the turkey baster method) or build some sort of blind!

Yeah, smart lil' buggers. It is comical though when they're so obsessed with you feeding them. They often swim up and down against the glass, then get a little tired and need a break, so they glide down for a landing. Sometimes they land on another blenny, or a crab, or another fish, and they all sit there, staring at me! If I wasn't there, they'd be biting or pinching each other.

One problem is that the lights are about 6" above the top of the tank and cause my reflection to appear in my pics and videos. I guess I need to build a canopy.

[Chasmodes]

Here's another video of my daughter feeding the fish last night. After the chopped clams were devoured, they skilletfish didn't want to leave her hand!

https://www.youtube.com/watch?v=bBYJGaUc_Q0

I'm not sure what's going on with the large killifish. A white spot showed up the other day on its side. Yesterday, it looked a little better and today even better. Perhaps its own immune system is fighting it off? If not, I'd have to find a way to trap that fish and provide treatment.

[Subsea]

Originally Posted by Chasmodes

I have some updates on my 20g long. The Ulva is pretty much gone. I'm not sure that the parameters are right from growing macros in this tank (light, etc.), plus, I'm sure that the shrimp and crabs eat some of it. I probably won't add much until I get the main tank set up. I can't tell of the other macro is growing or not. There are some parts that seem to, and others I'm not so sure about. It looks good in the tank still, and provides good cover for the smaller fish, so I'm leaving it in there. The sea grasses have died off, so that experiment ends until I get the main tank set up. I have some cyanobacteria and some green hair algae areas on shells and sand where the most light hits that could be competing with the macros and seagrass for nutrients. Right now, I'm not too worried about this but would like to figure it out prior to setup of the main tank. We will see how that goes. I personally don't think it looks that bad as it still adds color, plus, the crabs and shrimp seem to eat it.

Both colonies of bryozoans are expanding across the tank glass on either end of my tank, in the darker areas. They look cool.

One thing that came in handy was the purchase of an automatic feeder to keep my fish fed while I was away on vacation. We couldn't find anyone reliable that new much about fishkeeping, so this was my solution. It worked out OK. The only issue that I anticipated was if the fish would actually adapt to and eat flake food or pellets, since, up until my trip, all they've eaten were live or frozen foods for the most part. My attempts at feeding them flakes were with mixed results. The gobies ate flakes with gusto. Some of the blennies ate the flakes, ingesting some or spitting out some, and other blennies ignored the flakes. The skilletfish ate flakes at times, but not often.

As far as pellets go, they were a little too big for most of my fish, and for the ones that tried to eat them, they spit them out at first and later kept attacking them until they were bite sized enough to eat them. The blennies broke them up and ate some, and then the gobies would follow behind and eat some of the fragments, while the skilletfish ignored the pellets altogether.

So, I made the decision to go with flakes in the auto feeder. I had no other choice.

After returning from my trip, I noticed that all of the fish will eat flakes now. Gobies still eat them with gusto, as do the blennies if they're hungry. If the blennies aren't hungry, they ingest them and sometimes eat some of the "flavors" while spitting out others. Skilletfish will eat flakes at times, but not that much.

The gobies and blennies all grew and are all fatter than fat. A couple of the gobies grew almost a 1/2" while we were gone (about 10 days), which I thought was amazing.

Also, I thought that I had only two crabs in the tank, but as it turns out, there are three of them. I've identified two of the crabs as the white-clawed mud crab, a.k.a. the Harris mud crab (Rhithropanopeus harrisii). I'm not sure of the third crab species as it looks different, but, I really haven't had a good look at them. Until now, the crabs have been hiding mostly. Recently, two of them come out during feeding time, and one of those is out foraging even while not feeding. In fact, last night, it was moving all over one of the oyster reef structures all the way to the water's surface.

From what I've read, they only grow to about an inch or so, and they aren't aggressive toward fish or shrimps. I'd bet they'd eat them if they could catch them, but, so far, I've seen blennies actually land on them and the crabs just move away. They raise their claws if fish near them, but so far, haven't tried to grab any fish. The shrimp seem to be good at avoiding them. I also read that these crabs feast on all types of snails. I don't have snails in my tank at the moment, but if I add them, these will have to be stocked often to keep a population of them.

Here are a couple videos of my tank.

The first one pretty much follows the largest blenny of the tank:
https://youtu.be/mBe7XgwgZ-M

I tried to view the tank in general with this video, bouncing from one fish to another:
https://youtu.be/dc_YRaTyF0s

Hope you all like them.

Awesome vidio! The translucent grass shrimp rock. They are very brave to swim in the open like that. Did you blue to oyster structure together. I like it. My first marine aquarium was a Galveston Bay biotheme. I gathered a large oyster cluster that took up 1/3 of a 55G tank. No live oysters, but numerous barnecles that would sweep the water with their 1/2 fans. That was in 1971 and I have been addicted every since.

[Subsea]

Originally Posted by Chasmodes

I have an update for my oyster reef "system". The 20g long that started this thread is still going strong, with 6 small striped blennies, 5 small skilletfish, 5 naked gobies, two new juvenile killifish (probably juvenile mummichogs), 3 white-clawed mud crabs, an unidentified harmless isopod, a bunch of grass shrimp, and red macroalgae. All of the fish are fat and healthy. I tried to add three silversides but that didn't work out. They made it home just fine, which is what worried me the most. They were about 2 1/2" long and looked great in the tank, until the 2" clingfish killed and ate the first one. Another one was harrassed by the blennies and died, then devoured by the gobies and a crab. And the last one died of unknown causes during the night, probably killed by the same culprits. The only issue with the tank is that with the heavy bioload and feeding, cyanobacteria growing some pretty large patches. I don't think it looks necessarily bad, but I'd rather have those nutrients consumed by Ulva which hasn't done well in this tank.


The 20g high tank that I was using as a holding tank is now set up as a display also. I added a large artificial oyster cultch that I built for my large tank so that it could also grow life and additional bacteria needed to cycle my large tank when I set it up, in addition to the sand. This tank seems to grow Ulva pretty well. I have a small hang on back power filter and a bubble sponge filter in the tank, and two garage clamp on light fixtures overhead with LED bulbs. Cheap and simple, but it works. Over the weekend, my daughter and I went collecting again and found some inhabitants for this tank. We added 6 adult blennies, 2 jumbo skilletfish, 5 adult naked gobies, and two mummichogs to the tank. We had one jumbo skilletfish, a live barnacle, a bunch of grass shrimp, and 3 mud crabs in the tank prior to adding these. When rearranging the tank and moving the oyster shells around, I discovered that bloodworms were living in the tank. Awesome! A natural food supply! I also discovered a tunicate that is alive and well, and is growing much faster than I thought that they would. I think that the Ulva is really responding to the heavy bioload. I have a little bit of cyano in the tank and some hair algae, but the macros (Ulva and a red algae) are doing well. The fish have only been in the tank for a few days and are already feeding out of my daughter's hand. All of the fish were eating mysis shrimp the night that we introduced them to the tank. All are fat and healthy.

Here's a video of the blennies in the 20g high (sorry about the music, I figured it was better than hearing our clothes dryer running):
https://youtu.be/hn8xIsLFZ_8

The water parameters of both tanks are great. No ammonia, no nitrites and very little nitrate, so the bacteria and algae are doing their job.

I really like the way you have balanced this system. I love the biotheme. I especially like you collecting crittes with your daughter. To a kid, love is spelled "time" together.
Kudoes to you.

[Chasmodes]

Originally Posted by Subsea

Awesome vidio! The translucent grass shrimp rock. They are very brave to swim in the open like that. Did you blue to oyster structure together. I like it. My first marine aquarium was a Galveston Bay biotheme. I gathered a large oyster cluster that took up 1/3 of a 55G tank. No live oysters, but numerous barnecles that would sweep the water with their 1/2 fans. That was in 1971 and I have been addicted every since.

Thank you Subsea!

So many blennies to choose from in Galveston! That must have been an awesome tank.

Yeah, I got the most of the shells from restaurants and also shucked some that I got from the grocery story. Then, I matched them up and glued each halve together with Gorilla Glue. After that, I glued them one at a time, fitting each one into a cultch. In this tank, you're looking at the largest cultch. There are about 8 cultches that will all form my oyster reef in my 101 gallon tank eventually. I put them in these tanks so I could start collecting, and at the same time, get some bacteria cultured on the cultches and also the sand in both tanks. Kind of like a head start. I have one barnacle, LOL, that I didn't know was there until I rearranged everything. There is also one sea squire. I hope both survive, but they may not since these tanks are relatively newly set up (less than 3 months).

As far as the grass shrimp go, I put a bunch in both tanks. Only a couple have jumped out, and most have lived. In my other tank, the fish ganged up and killed the largest one and at it, then did the same thing to one more. I don't think any have been killed since in that tank, and in the 20g high, I don't think any have been eaten. But, I'm not around all of the time, so it is possible.

That's the one good thing, there are plenty of shrimp to catch and add to the tank to replace the ones that get eaten. They've lasted a lot longer than I ever thought that they would.

[Chasmodes]

The naked gobies are exhibiting more color than I thought that they ever would. Some of their fins are trimmed with yellow or red (depending on how the light hits them) and also they get dark and the lighter areas between their color bands get bold white dorsally. Also, in these videos, it's easy to see the difference between the male and female blennies. The males have a blue spot on the front of their dorsal fin.

I figured out a way to get the fish to almost figure out that I'm not there. I need to build a canopy for my lights. For now, the cardboard box that my glass tank top came in fits perfectly as a temporary solution, placed there when I view the fish and removed when I'm done. I'll try and get a non-feeding video today and post it here. The fish tend to settle down and do their thing after feeding time is over, somewhat. They forage, get into territorial disputes, asserting dominance and challenging the pecking order, moving from one oyster shell refuge to another, chasing opponents...and looking for me.

But for now, here's another feeding video. Hope y'all aren't sick of my thread. I figure that this thread helps document my progress to my larger goal, the 100g tank once set up. I'm kind of learning as I go as these tanks are really a big experiment This video is amusing because the fish steal the food away from my daughter twice:

https://youtu.be/Iz9iLiCqUNE

[Chasmodes]

Not so good update of the 20g high... The tunicate and barnacle died. I'm bummed, but I expected that to happen. The fish are doing well for the most part. The largest killie still shows a spot on its side, but other than that, seems healthy and eating well, with no sign of distress. Both killies looked great until last night when I noticed that them and a few gobies had beat up tails. I watched them for about an hour after feeding to see who the culprit was, but still don't know. They all pick on each other a bit... blennies chase blennies, gobies chase gobies, killies chase killies, skilletfish chase anyone away from their hiding spot, and they all chase each other a little bit. But, none of them seem to do much damage. Well, except for the smallest blenny. I caught it biting a gobies tail, latching on hard and with a ripping motion. So, maybe I found the culprit. None of the fish go into hiding or seem stressed, so I hope everyone heals and moves about their daily routine.

The grass shrimp numbers are declining. Other than a couple carpet surfers, most of them probably were prey to the fish, although I didn't witness any predation. The crabs are a different story. I never see them, although I know that they are there, because they leave behind their molted shells. I'll have to check the tank at night to see what is going on. I still haven't done that.

I figured out a way to get them to behave naturally and not beg for food. Feed them. Duh...!!! But, that alone doesn't work because no matter how fat they are, they still beg for more. So, I set up my temporary "canopy" and also set up a DIY blind using shop clamps, a towel, a bungee cord and a hanger. After a couple minutes, they forget that I'm there. In the video linked below, you can see them acting more naturally. That is, until one of them spotted me moving at the end. Also, in the video, I came to realize that my killies might be a pair. Maybe some spawning activity? Hope y'all like it: https://www.youtube.com/watch?v=mTOJrQa9uRM