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nmotz
08/11/2016, 12:15 PM
Just wanted to post some thoughts I have regarding mantis shrimp feeding since it seems to be a common question for new hobbyists.

-Mantis shrimp seem to rarely ever be "full." My Peacock would certainly like to eat everyday, several times/day. Anything that enters the water is considered food until proven otherwise. She will often attack bags that I have floating in the water during temp acclimation to see if there is food inside. My N. Oerstedii would eat all day long until the supply of live food ran out.

While it is not necessary to feed every day, the only thing it'll hurt is water quality IMO. If you want to minimize nutrient build-up, then one feeding per 2-3 days is acceptable, but anything more than that is starving a mantis IME. They might survive it, but they won't be as healthy/active. My opinion is that you should add more filtration capacity (i.e. better skimmer, macroalgae, more LR, carbon, GFO, etc) to enable increased feedings.

-Recommended portion size is a morsel no larger than about half the size of the upper carapace. That doesn't mean mantis shrimp won't enjoy larger portions. In one day I've seen my Peacock eat at least 2 emerald crabs that were probably 3/4-1" in diameter and still head out on foraging expeditions. My Peacock sweeps the entire tank many times throughout the day, digging in the substrate, moving rocks that aren't too big, etc.

While some report a decrease in activity if they feed too much, my opinion is that this is the case only when a mantis is fed too much frozen food. If they're trained to "wait for the tongs to feed them" then they do often become lethargic and bound to their burrows. Conversely, if they know that their foraging will often be rewarded with live prey, they'll be much more willing to explore. This is a double-edged sword of course because live food is much more costly, there are some good live food choices that are manageable if bought in bulk (list at bottom).

-It's important to note that mantis shrimp living in PVC pipes like mine seem to have trouble breaking through the toughest snail/hermit crab shells. This is because they don't have the depth/consistency of substrate needed to immobilize the prey before striking it.

In the wild, Peacocks press the shell into the substrate and strike, allowing all of the force to be applied towards breaking the shell. In a PVC burrow, Peacocks can often be seen trying to press the shell down into the PVC itself similar to their tactics in the wild. Of course, the PVC prevents this and the end result is the mantis essentially knocking the shell all about the interior of the burrow without doing any real damage. Peacocks grow frustrated by this and will often expel the snail. Mine seems to have memorized which snails in the tank are off limits.

The moral is that you can't just throw a bunch of snails in the tank and walk away. Confirm that the mantis is able to break into them. If it can't, get smaller snails. If you see a bunch of snails crawling around on your glass with obvious damage, that confirms your mantis tried but was unable to break them.

-Mantis shrimp seem to be expert scavengers. If you want to make feeding frozen food more interesting, try putting a piece of frozen food in an empty shell and hide that somewhere in the tank. The mantis will smell it and come out looking. IMO it's better than just watching them take the food off the feeding utensil.

Mantis shrimp have a wonderful sense of smell. I once noticed my Peacock swimming up into the water column underneath the spot where water returned to the tank from my HOB refugium. It seemed she was trying to swim up the waterfall into the refugium . Sure enough, when I looked in the refugium, one of the emerald crabs I was storing there had died, and she smelled it.

Here is my list of "interesting" food options, both frozen and live plus their sources (note the diversity, which is important for proper nutrition):
-Emerald crabs, best purchased at LFS. If you do some shopping or speak to the manager, they might be able to cut you a nice deal. I get mine for $3 a pop, so obviously too expensive to be a daily option.
-Brine shrimp, again best purchased at an LFS. Relatively cheap at around $2 for an order that will last you several feedings. Trick is to keep the brine shrimp alive that long! I usually add some Selcon to their water and a few drops of Seachem to neutralize ammonia. For oxygenation I stir the water vigorously a few times per day. They usually live at least a week using these methods.
-Frozen clams on the half shell: I get the Hikari brand but there are others. These last a really long time and are great to soak in Selcon. Everything frozen should probably be soaked in Selcon for 5 mins or so to enhance nutrition. I usually place these as far from the burrow as possible. The smell will lure them from the burrow and it's fun to watch them hunt down the source.
-Frozen krill/squid/shrimp: various owners have reported that their mantis shrimp seem picky about these meats. Some love krill, but hate squid, or vice versa. Find what works and go with that. Very cheap option, and don't forget to enrich with Selcon.
-Ghost (glass/ditch) shrimp: these shrimp are brackish but are normally sold after being held in freshwater. I've never noticed any adverse affects of feeding freshwater shrimp, but it's an option that I don't use very often just to be safe. They are one of the cheaper live food options however. You can usually get 5 or 6/$1.
-Periwinkle snails: great for smaller mantis shrimp especially, these can be bought in bulk from reefcleaners.org. They're $0.15 each. Order 10 and you'll receive about 50, no joke.
-Dwarf cerith/nassarius snails: can be found at an LFS but I like to buy in bulk from reefcleaners. You can specify the sizes that you want. I've found my Peacock struggles to get into the larger Nassarius snails but loves digging in the sand for small ones. Pay for 5-10 snails and you'll get at least triple that for free.
-Hermits: size is important when buying hermits for food. Too big and the mantis won't be able to break them. Too small and the mantis might not exert the effort. I haven't had much luck with hermits, but they're relatively inexpensive and also act as valuable CUC members. Best to get these guys at the LFS in my experience.

Jlentz
08/21/2016, 08:50 PM
I get the tiny hermits and massive snails for cuc. Everything else is food. Though mine doesn't seem to care much about regular crabs for some reason.


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nmotz
08/22/2016, 10:29 AM
Yeah it's really interesting the different food preferences they have. Makes me think that in the wild where they were collected, they must have become more accustomed to certain types of prey. Perhaps the availability of snails is greater than hermits in some areas so they develop a taste for snails and not so much hermits? Just a theory, but interesting nonetheless.

Jlentz
08/24/2016, 06:46 PM
That's my thinking as well. I've heard it depends on how they are kept as well. Mine has a blenny and damsel as tank mates. It's also lps bright. With some Sps really high up in the tank.

He's taken out some of the big turbos in the last week and a conch. So some shift in the violence but I made a massive sandbed change in the tank in June.


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