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View Full Version : Inches of Fish per Gal ???? What you guys have !!Research !!


Paul Davies
01/18/2006, 08:28 AM
Gals/ Guys,

I am doing some research on the boundaries of captive specimines and would like your help in this matter !

Can you reply to this post with your inches of fish per gal you currently have and weither or not you mean Americal gallons or Brittish.

Also if you have 2 secs, could you add the number of fish in total you have plus if you have a reef of fish oly.

thanks in advance.

Paul

kbmdale
01/18/2006, 08:32 AM
I have 8" of fish total in a reef 30g

As far as a calculator, you don't count the tail when you add your fish up...Here is the one I use.

http://www.aquariumadvice.com/calcs2.php?type=fishcapacity

Paintbug
01/18/2006, 11:03 AM
right now i have about 1" of fish per 6.81 water. as a general rule for SW its about 5" of fish per gallon should be the max bio-load. but theres lots of things to consider. 6" of clowns is not going to have the same bio-load as 6" of a Tang. thats why not alot of pepole use a general rule like that.

eidillitih
01/18/2006, 11:12 AM
<a href=showthread.php?s=&postid=6529700#post6529700 target=_blank>Originally posted</a> by Paintbug
right now i have about 1" of fish per 6.81 water. as a general rule for SW its about 5" of fish per gallon should be the max bio-load. but theres lots of things to consider. 6" of clowns is not going to have the same bio-load as 6" of a Tang. thats why not alot of pepole use a general rule like that.


5" of fish per gallon:eek1: I hope you meant 1in per every five gallons. Yes, it also depend on the species.

Paintbug
01/18/2006, 12:05 PM
opps :D yes 1" per 5 gallons. nice catch.

techigirl78
01/18/2006, 12:22 PM
125 gal reef - 7 fish - ~15"

90 gal reef in progress / 70 gal sump/refugium - 3 fish - ~ 12"

Clayman
01/18/2006, 12:28 PM
100 gal mixed reef. This is what I have planed for the tank. I already have the first three on the list the rest is still to come.

2 false percs
6 blue/green chromis
1 royal gramma
1 firefish
1 purple tang
1 flame angel
1 mandarin

kbmdale
01/18/2006, 12:32 PM
<a href=showthread.php?s=&postid=6530351#post6530351 target=_blank>Originally posted</a> by Clayman
100 gal mixed reef. This is what I have planed for the tank. I already have the first three on the list the rest is still to come.

2 false percs
6 blue/green chromis
1 royal gramma
1 firefish
1 purple tang
1 flame angel
1 mandarin

2 false percs = 4"
6 blue/green chromis = 9"
1 royal gramma = 2"
1 firefish = 2"
1 purple tang = 4"
1 flame angel = 3"
1 mandarin = 2"

And that is assuming the fish are on the small side. I think you will way overload that tank if you add all those.

LTJGAlex
01/18/2006, 12:39 PM
Remember that the answers to this age-old question will depend on who's answering. Tang Police will tell you a totally different thing than normal hobbyists.

stevedola
01/18/2006, 12:44 PM
75 gallon-
1 sohal
1 powder
1 yellow
2 percs
5 chromis
1 goby
1 hawk
1 6 line

chris2222000
01/18/2006, 12:53 PM
125 gallon Reef
--------------------------------
1 yellow tang- 5"
1 nasty tomato clown- 4"

ratherbediving
01/18/2006, 01:29 PM
You almost need an 'inch multiplier' in order to answer this question IMO--- for example, 7" of tang should be equal to at least 21" of chromis... or something like that. Although fish have different metabolisms, a 4" fish with the same shape as a 2" fish is 8 times as large, not twice as large.

My biggest fish by far is a Royal Gramma. Probably not quite 4" not including the tail, but larger than 3". It is over twice the size of my bicolor blennie, even though the bicolor is almost as long.

55 gallon tank

Royal Gramma 3" (4"?)
Bicolor Blennie 3"
Yellow Watchman Goby 2"
Ocellaris clownfish 3"
Venderbilt chromis 2"

13"-- 1" of fish per 4.23 gallons

Planning for adult sizes (from liveaquaria.com)
Royal Gramma 3" (?)
Bicolor Blennie 4"
Yellow Watchman Goby 3"
Ocellaris clownfish 4" (I'd be surprised if mine got that big)
Venderbilt chromis 4" (wow... seems large.)

18"-- 1" of fish per 3.06 gallons

I'd LOVE to get a 6 line wrasse, but I know I should probably hold off. :sad2:

thehedge
01/18/2006, 01:33 PM
75 gallon

Rosy Fin Fairy Wrasse 3"
Mystery Wrasse 2"
Bluesided Fairy Wrasse 2"
Yellow Fin Fairy Wrasse 2"
2 Perculas 1" each
Yellow Clown Goby 1"
2 Banded Shrimp Gobies 1" each

14" total

tsquad
01/18/2006, 01:35 PM
<a href=showthread.php?s=&postid=6530808#post6530808 target=_blank>Originally posted</a> by ratherbediving
You almost need an 'inch multiplier' in order to answer this question IMO--- for example, 7" of tang should be equal to at least 21" of chromis... or something like that. Although fish have different metabolisms, a 4" fish with the same shape as a 2" fish is 8 times as large, not twice as large.


Agreed. Would you put a 24" Sohal in a 150g tank? No. That's about 1"/6g. You could put twelve 2" chromis in there and be fine though.

onereefnotenuf
01/18/2006, 01:51 PM
in my 125 i have 8 us gallons per inch
1 sailfin tang 5"
1 kole tang 5"
1 flame angel 3"
1 flame hawkfish 2"

daveNandi
01/18/2006, 01:56 PM
currently have a 46 gallon (US) reef with
2 inch Ocelaris clown
2 inch orchid dottyback
2 inch psychadelic mandarin
1 inch Red headed goby

used to have a couple more fish in the tank, but one met the powerhead intake and another just died (my son's favorite, a wrasse).

My wife's always begging for a few more inches, but I prefer to keep the tank understocked to make maintenance easier.

David

zukihara
01/18/2006, 02:03 PM
Wouldn't you have to factor in the total system volume to do this calculation accurately? Maybe even subtract the amount of water displaced by any live rock? If its 50 lbs of rock in a 180 no big deal but say 250 pounds in a 110, thats different.

Paul Davies
01/18/2006, 02:08 PM
Very true guys, didnt think of that, I would make a difference with an 8" puffer rather than 6 or 7 chromis.

Billybeau1
01/18/2006, 02:36 PM
72 us gallons - fish only - 6 fish - total 17 inches.

I'm about maxed out. :D

kbmdale
01/18/2006, 02:42 PM
<a href=showthread.php?s=&postid=6531032#post6531032 target=_blank>Originally posted</a> by daveNandi

My wife's always begging for a few more inches, but I prefer to keep the tank understocked to make maintenance easier.

David

Careful there stubby :lol:

kbmdale
01/18/2006, 02:44 PM
<a href=showthread.php?s=&postid=6531089#post6531089 target=_blank>Originally posted</a> by zukihara
Wouldn't you have to factor in the total system volume to do this calculation accurately? Maybe even subtract the amount of water displaced by any live rock? If its 50 lbs of rock in a 180 no big deal but say 250 pounds in a 110, thats different.

I agree but to an extint. I mean you may have a 50g display with 20lbs of LR and a 150g fuge with 100lbs of live rock, but you still wouldn't call it a 200g tank with 120ls of rock, and a tang wouldn't be very happy due to tank lenght not water volume.

kbmdale
01/18/2006, 02:45 PM
<a href=showthread.php?s=&postid=6530473#post6530473 target=_blank>Originally posted</a> by stevedola
75 gallon-
1 sohal
1 powder
1 yellow
2 percs
5 chromis
1 goby
1 hawk
1 6 line

I hope thats a joke.

zemuron114
01/18/2006, 02:50 PM
55 gallon - 12-13" roughly
110 gallon - 25" (i have a 7" golden eel... do eels count? lol)

thats it

zukihara
01/18/2006, 02:58 PM
Kmdale, I wasn't speaking of tangs:)
I was merely pointing out there are intricacies around determining "boundaries of captive specimens" cited as the goal in the original post. Im saying 2 people have 120g tanks. Both have 24" of fish. One has a 55g sump and one doesn't. Well, that's less inches per gallon for that guy. More rock would also displace water volume but would provide for a bigger fishload.

Just saying when determining these boundaries the original poster might want to define his research parameters a bit or any research may very well be wholely inaccurate.

stevebydac
01/18/2006, 02:59 PM
<a href=showthread.php?s=&postid=6530808#post6530808 target=_blank>Originally posted</a> by ratherbediving
You almost need an 'inch multiplier' in order to answer this question IMO--- for example, 7" of tang should be equal to at least 21" of chromis... or something like that. Although fish have different metabolisms, a 4" fish with the same shape as a 2" fish is 8 times as large, not twice as large.




Agree with this 100%. Also, three other factors:

1) The "Eels Rule" - a 24" moray is a medium sized fish. A 24" puffer, grouper, trigger, etc. is a HUGE fish.

2) Less active fish need less room. A lionfish needs less than a same-sized tang.

3) Territorial/ highly aggressive fish need more room than passive fish.

kbmdale
01/18/2006, 03:39 PM
<a href=showthread.php?s=&postid=6531528#post6531528 target=_blank>Originally posted</a> by zukihara
Kmdale, I wasn't speaking of tangs:)
I was merely pointing out there are intricacies around determining "boundaries of captive specimens" cited as the goal in the original post. Im saying 2 people have 120g tanks. Both have 24" of fish. One has a 55g sump and one doesn't. Well, that's less inches per gallon for that guy. More rock would also displace water volume but would provide for a bigger fishload.

Just saying when determining these boundaries the original poster might want to define his research parameters a bit or any research may very well be wholely inaccurate.


but the sump doesn't come into play with the inches per gallon. Your fish can't swim in the sump. Like I said you can't stock a 50 gallon tank with a 50 gallon sump like you would a 100 gallon tank. You have to stock it like a 50 gallon tank.

techigirl78
01/18/2006, 03:49 PM
<a href=showthread.php?s=&postid=6531394#post6531394 target=_blank>Originally posted</a> by kbmdale
Careful there stubby :lol:

:lol: :lol: :lol:

ratherbediving
01/19/2006, 01:47 PM
<a href=showthread.php?s=&postid=6531887#post6531887 target=_blank>Originally posted</a> by kbmdale
but the sump doesn't come into play with the inches per gallon. Your fish can't swim in the sump. Like I said you can't stock a 50 gallon tank with a 50 gallon sump like you would a 100 gallon tank. You have to stock it like a 50 gallon tank.

For many reasons, a gallons per inch rule does have some issues, but I do think it is a useful guideline-- unless we could think of something to replace it.

You could argue both points--
If you had two systems, one with a 50 gallon display tank and a 50 gallon sump, the other with a 100 gallon tank and no sump-- and each system had the same amount of live rock and used the same skimmer... and each person performed the same water change routine... then the systems should be able to provide for the same bioload, or the same number of fish "inches". That is not saying a tang would be as happy in either system; the 50 gallon tank is too small for a tang for other reasons besides the bioload. It just means you could have the same number of chromis :)

However, if you add too many caveats or calculations to the rule, then the rule becomes to complicated or controversial to use. What happens when someone uses a larger skimmer? What about people who feed their corals heavily (or who target feed their anemone)? What about people who use a refugium to export nutrients, shouldn't that help as well? It might be better just to keep the rule as 5 gallons in the display tank per inch, if that is how people currently interpret the rule.

On first glance, I run my tank heavily stocked, at a little over 3 gallons an inch (planned adult sizes). However, I use a sump with a refugium, use a skimmer (over)rated to a 200 gallon system and have fairly small fish. That makes me think that I should be okay with the fish load I have. If I had never heard of the '5 gallons per inch' rule, I would really have no idea however if I was overstocked or not... it is useful as a rough guideline/ starting point IMO.

kbmdale
01/19/2006, 02:01 PM
<a href=showthread.php?s=&postid=6538966#post6538966 target=_blank>Originally posted</a> by ratherbediving
For many reasons, a gallons per inch rule does have some issues, but I do think it is a useful guideline-- unless we could think of something to replace it.

You could argue both points--
If you had two systems, one with a 50 gallon display tank and a 50 gallon sump, the other with a 100 gallon tank and no sump-- and each system had the same amount of live rock and used the same skimmer... and each person performed the same water change routine... then the systems should be able to provide for the same bioload, or the same number of fish "inches". That is not saying a tang would be as happy in either system; the 50 gallon tank is too small for a tang for other reasons besides the bioload. It just means you could have the same number of chromis :)

However, if you add too many caveats or calculations to the rule, then the rule becomes to complicated or controversial to use. What happens when someone uses a larger skimmer? What about people who feed their corals heavily (or who target feed their anemone)? What about people who use a refugium to export nutrients, shouldn't that help as well? It might be better just to keep the rule as 5 gallons in the display tank per inch, if that is how people currently interpret the rule.

On first glance, I run my tank heavily stocked, at a little over 3 gallons an inch (planned adult sizes). However, I use a sump with a refugium, use a skimmer (over)rated to a 200 gallon system and have fairly small fish. That makes me think that I should be okay with the fish load I have. If I had never heard of the '5 gallons per inch' rule, I would really have no idea however if I was overstocked or not... it is useful as a rough guideline/ starting point IMO.

Good Post...I agree

zukihara
01/19/2006, 02:08 PM
Ok let me try this from another angle. If you are talking "boundaries" then that would infer "limits", not acceptable stocking parameters.
Unless I am just insane, having more water volume in a remote location would allow more inches of fish(generally speaking) than without. This is EXACTLY what people do every day in this hobby. We use external means to help stability, manipulate ph, export nutrients, provide oxygen and on and on. All this allows for a higher bioload in the display.
Indeed maybe the research would be better termed "manipulating the boundaries of captive systems" or maybe I just misunderstood the original question:)

All I'm saying is it's fairly impossible to establish an inch per gallon rule without setting some limits on variables.

zukihara
01/19/2006, 02:12 PM
Hmmm without variables, you can probably just look up various aquaculture references involving fish farming to get an answer. Say, how many catfish per acre, prawns, etc.