Amphipods Eating Coral

[Seek&Reef]

I know this is highly debated, but without a doubt my coral is being eaten by these amphipods. They started on a war coral that was recovering from accidental bleaching. They have now moved on to a seperate war coral on the same rock. This war coral was growing faster than anything in the tank and had already encrusted off the plug and onto the rock. Its now just on top of the plug. Then this morning I noticed they have eaten my candy cane flesh from the bottom up. The candy cane was extremely healthy and all 3 heads were about to split. Overnight the flesh over the base was decimated. I have 3 wrasses, one of which is a melanurus who does peck at them but the pods are nocturnal so it doesn’t make a big difference. I am contemplating using interceptor, but am hesitant as I have so much life from my ocean rock. Bivalves, tunicates, brittle stars, spaghetti worms, feather dusters, etc. Please help…

 

[elysics]

Don't nuke your tank just yet.

Did you accidentally feed more than usual in the last month or two? Or start feeding much less in recent weeks?

There are thousands of different amphipod species, but if you got one of the common ones and not some super pest, they might be eating your corals because they are starving, which might be because you were feeding more in the past and their numbers exploded.

Maybe broadcast feed the tank a tiny bit more but not much more than now.

 

[Seek&Reef]

I was feeding pretty heavily for a while and started feeding less when I saw their numbers explode. They weren't eating corals just yet but obviously knew there were way too many regardless. If I feed more to keep them happy what will happen when I eventually need to stop feeding so much? Then we are back at square one where they start eating coral again.

 

[elysics]

I was feeding pretty heavily for a while and started feeding less when I saw their numbers explode. They weren't eating corals just yet but obviously knew there were way too many regardless. If I feed more to keep them happy what will happen when I eventually need to stop feeding so much? Then we are back at square one where they start eating coral again.

The issue is going back and forth with sharp jumps between feeding too much and too little, instead of slooooowly ramping up and down.

I wouldn't worry about their numbers at all as long as the amount you are feeding is the amount you want to keep feeding for the health of your tank. The population will adapt. There are only too many if you suddenly change the amount you feed.

And your corals suffering because of the sudden lack of nutrient input might be a compounding factor.

If i were in your shoes i would feed more than you are now, but a bit less than you were before. Enough so they'll be hungry but not starving. Get your coral health in order, and then slowly ramp towards the amount you want to keep longterm.

 

[Seek&Reef]

The issue is going back and forth with sharp jumps between feeding too much and too little, instead of slooooowly ramping up and down.

I wouldn't worry about their numbers at all as long as the amount you are feeding is the amount you want to keep feeding for the health of your tank. The population will adapt. There are only too many if you suddenly change the amount you feed.

And your corals suffering because of the sudden lack of nutrient input might be a compounding factor.

I currently dose no3 and po4 and keep it steady, and I target feed my coral.

 

[elysics]

I edited another paragraph in. Just feed more again and slowly ramp down the amount, the change was just too fast.

Or alternatively, if you've got nerves of steel, do nothing and wait for them to crash. might cost you another couple corals or so though. Putting them on a frag rack away form the bottom might help

I learned this the hard way, lost about 12 zoa varieties this way in several waves until i learned my lesson.

 

[Seek&Reef]

I’ll see if I can’t get them fed more to slow down the coral loss. I am honestly surprised these amphipods aren’t talked about very often

 

[HBtank]

I’ll see if I can’t get them fed more to slow down the coral loss. I am honestly surprised these amphipods aren’t talked about very often

Because every healthy tank is loaded with amphipods, and very very few report anything like this; if and when they do, others generally dismiss it as scavenging dead material (or it being another issue/pest). Maybe it is a specific species, or a combination of factors. If it was just hungry amphipods, I think it would be far more common. I certainly have seen examples of it reported by people who seem to know what they are looking at, so it's hard to dismiss.

 

[ZombieEngineer]

Amphipods are herbivores and detrivores. They will not eat living coral. This is like saying maggots killed the roadkill.

You need to see what changed in your tank. Could be a broken magnet, cracked equipment leaching copper, nudibranches, salinity swing, low alkalinity, etc. Check all of your parameters and post what they are currently.

Age and size of tank?

How long have corals been present?

Do you dip and/or quarantine corals?

 

[Pkunk35]

I kinda agree that the coral has to start going downward before amphipods begin to devour coral, or at least this is my experience. I have seen them eat a mini colony of my exospheres in one night, but it wasn’t until they started to decline for a couple days and then the critters devoured them, this happens to all my zoas that decline. Highly debatable for sure tho if the amphipods are the actual cause of decline, I just don’t think so.

the talk of nutrient input being a main reason for amphipods eating coral is interesting and I def think it contributes to these problems in my own tanks.

 

[elysics]

Amphipods are herbivores and detrivores. They will not eat living coral. This is like saying maggots killed the roadkill.

There are also omnivore and carnivore amphipods, thousands of species wasn't an exaggeration. Hell i've got some tiny amphipods in my tank that build tubes and have big claws that they use like spearer mantis shrimps to kill zooplankton and such (those are not the ones that ate zoas in my tank though). I think i got 4-5 different kinds in my tank, maybe more.

but it wasn’t until they started to decline for a couple days and then the critters devoured them

When it happened to me, the zoas were not in decline at all. 2 polyp plugs or 30 polyp colonies, didn't matter. Whole thing in peak health, then i see 1 polyp suffering and amphipods gnawing at it, polyps around that closing up because they are being trampled, polyps on the other side of the colony still perfectly fine. Then the polyps around the initial one suffer and so on until the colony is gone. Always just one colony though, the ones next to it or across the tank looking healthy as ever. And then once the colony is gone the whole thing might start again somewhere else. Never had it in two places at the same time i don't think.

If i took a suffering colony up from the ground and put it high up on a frag rack where amphipods couldn't get to as easily, the death spiral would stop, at least for that colony.

 

[vetteguy53081]

I know this is highly debated, but without a doubt my coral is being eaten by these amphipods. They started on a war coral that was recovering from accidental bleaching. They have now moved on to a seperate war coral on the same rock. This war coral was growing faster than anything in the tank and had already encrusted off the plug and onto the rock. Its now just on top of the plug. Then this morning I noticed they have eaten my candy cane flesh from the bottom up. The candy cane was extremely healthy and all 3 heads were about to split. Overnight the flesh over the base was decimated. I have 3 wrasses, one of which is a melanurus who does peck at them but the pods are nocturnal so it doesn’t make a big difference. I am contemplating using interceptor, but am hesitant as I have so much life from my ocean rock. Bivalves, tunicates, brittle stars, spaghetti worms, feather dusters, etc. Please help…

Based on their larger size, they often eat algae which coral contain for zooxanthellae and will appear that theyre going after coral

 

[HBtank]

There are also omnivore and carnivore amphipods, thousands of species wasn't an exaggeration. Hell i've got some tiny amphipods in my tank that build tubes and have big claws that they use like spearer mantis shrimps to kill zooplankton and such (those are not the ones that ate zoas in my tank though). I think i got 4-5 different kinds in my tank, maybe more.



When it happened to me, the zoas were not in decline at all. 2 polyp plugs or 30 polyp colonies, didn't matter. Whole thing in peak health, then i see 1 polyp suffering and amphipods gnawing at it, polyps around that closing up because they are being trampled, polyps on the other side of the colony still perfectly fine. Then the polyps around the initial one suffer and so on until the colony is gone. Always just one colony though, the ones next to it or across the tank looking healthy as ever. And then once the colony is gone the whole thing might start again somewhere else. Never had it in two places at the same time i don't think.

If i took a suffering colony up from the ground and put it high up on a frag rack where amphipods couldn't get to as easily, the death spiral would stop, at least for that colony.

This is still extremely rare, when amphipods are anything but rare, so the skepticism is understandable.

 

[Seek&Reef]

Amphipods are herbivores and detrivores. They will not eat living coral. This is like saying maggots killed the roadkill.

You need to see what changed in your tank. Could be a broken magnet, cracked equipment leaching copper, nudibranches, salinity swing, low alkalinity, etc. Check all of your parameters and post what they are currently.

Age and size of tank?

How long have corals been present?

Do you dip and/or quarantine corals?

Po4 dosed: stays around .05-.10ppm
No3 dosed: stays around 5-15ppm
Alk: stays at 8.8-9dkh
Mg: 1400-1450
Ca: 445
Ph: 8.2-8.3

recent icp show slightly elevated zinc and low manganese and low iodine.

corals have been in tank for maybe 2 months. I’ve had a hammer coral in there for 5 months. Everything is doing good. Gonis, Cyphastrea, stylophora, hammers, torch, Duncan’s, blasto, and Gsp.

tank 6 months old. 20lbs ocean rock, 80ish lbs dry Marco rock. 150 gallon.

I’ve already beat bryopsis & small cell amphidinium. Now battling large cell amphidinium by dosing silicates again to induce a diatom bloom. I think the amphipods exploded in size from the diatoms when I fought sca. Then when I quit dosing it they obviously started to recede taking their primary food source with it.

I know they are eating healthy tissue. I looked at my war coral before I went to bed and then this morning. They chewed through a solid 1/4” off the side of the frag plug. That side was already encrusted on to the rock. I hope you never find out that there are coral eating amphipods. But believe me there are

 

[Seek&Reef]

Based on their larger size, they often eat algae which coral contain for zooxanthellae and will appear that theyre going after coral

I’ve seen them crawl across my zoas and keep expecting them to eat them but they haven’t. So I know they eat other things. But it seems some have a taste for coral or as you said the algae within the coral lol

 

[Seek&Reef]

Based on their larger size, they often eat algae which coral contain for zooxanthellae and will appear that theyre going after coral

I’ve seen them crawl across my zoas and keep expecting them to eat them but they haven’t. So I know they eat other things. But it seems some have a taste for coral or as you said the algae within the coral l

There are also omnivore and carnivore amphipods, thousands of species wasn't an exaggeration. Hell i've got some tiny amphipods in my tank that build tubes and have big claws that they use like spearer mantis shrimps to kill zooplankton and such (those are not the ones that ate zoas in my tank though). I think i got 4-5 different kinds in my tank, maybe more.



When it happened to me, the zoas were not in decline at all. 2 polyp plugs or 30 polyp colonies, didn't matter. Whole thing in peak health, then i see 1 polyp suffering and amphipods gnawing at it, polyps around that closing up because they are being trampled, polyps on the other side of the colony still perfectly fine. Then the polyps around the initial one suffer and so on until the colony is gone. Always just one colony though, the ones next to it or across the tank looking healthy as ever. And then once the colony is gone the whole thing might start again somewhere else. Never had it in two places at the same time i don't think.

If i took a suffering colony up from the ground and put it high up on a frag rack where amphipods couldn't get to as easily, the death spiral would stop, at least for that colony.

this is exactly what I am seeing. I ordered some interceptor and am going to feed the tank heavily for the time being. Then when it comes in I will do the dosing methods and reseed the tank with copepods again. What did you do to break the cycle

 

[Tired]

Large amphipods will definitely chew on corals if they're low on food. They can also annoy the coral into ill health by sheer numbers, then chew on it once it's unhealthy.

What fish do you have, in what size tank? Predators can be a big help, and most fish are amphipod predators. Might be time to add something semi-nocturnal, or something with a decently big mouth for its size.

Any chance you can get a Hasselt's goby? They're supposedly very good at stripping a tank of pod-type critters. Downside is, they might /all/ your pods, not just most of them. Pretty uncommon in the trade, but should be compatible with most fish, if you can get one.

 

[Seek&Reef]

Large amphipods will definitely chew on corals if they're low on food. They can also annoy the coral into ill health by sheer numbers, then chew on it once it's unhealthy.

What fish do you have, in what size tank? Predators can be a big help, and most fish are amphipod predators. Might be time to add something semi-nocturnal, or something with a decently big mouth for its size.

Any chance you can get a Hasselt's goby? They're supposedly very good at stripping a tank of pod-type critters. Downside is, they might /all/ your pods, not just most of them. Pretty uncommon in the trade, but should be compatible with most fish, if you can get one.

I have clown pair, exquisite wrasse, fairy wrasse, and melanurus wrasse. Purple tang, bristletooth, and chocolate tang will be out of qt in 3 weeks. I looked into a clown goby. I assume thats the same one. Its a nocturnal goby

 

[Alexraptor]

Amphipods will definitely, without a shadow of a doubt, feed on healthy coral. I've had it happen often enough in my systems, and particularly with Zoas.

I do think people have the right of it about massive populations vs lack of food, as I did manage to sort out the problem by baiting and trapping a crapload of them in one tank, and with my young G. Ternatensis culling their numbers in the other.

 

[Tired]

A clown goby is a completely different fish than a Hasselt's, and is one with a small mouth and a tendency to not start eating in captivity. A watchman goby would be a better pick, if you want a goby that should go after amphipods, or maybe some sort of basslet. Or a geometric pygmy hawkfish should decimate the big ones.