Emerald crab eating fish?!

[OneRobertG]

I have to admit I'm fairly new to all of this but quite addicted. I have a 55 gallon set up. Been monitoring levels twice daily- Ammonia = 0, Nitrite = .5, Nitrate = 5. I've been setup for a couple of weeks now with live rock and live sand. I bought 5 green chromis yesterday. They all looked really healthy and were loving the flow in the new tank and immediately all eating. This morning I wake up and one them has a large red mark near the tail. So I'm immediately suspicious that one of the Emerald's did it but figured I'd wait and see if the fish got better. So later tonight I see the Emerald eating a dead fish!!! So I don't know if the fish got sick and died. If the Emerald gashed it, it got sick and died. Or the Emerald outright killed it. By the way all of the other fish are healthy.

These guys seem like they're aggressive little bastards, am I wrong? I want to get them out as soon as possible if you guys think they're culprit.

 

[Tylt33]

I've been through a few tanks now, and have decided that nothing with hands goes in my tanks. I don't trust hermits, I don't trust emeralds.

 

[OneRobertG]

Crap...the chromis the Emerald was eating wasn't even the one with the mark. The one with the red mark was dead though too just in the back of the tank

I'm thinking they must have died first. I don't think the crab would have killed two of them. These fish do seem to like to be right up against the rocks where these crabs hang out though.

I don't know what the heck is going on, everyone else looks good.

Parameters: Ammonia = .25, Nitrite = .5, Nitrate = 5

 

[LisaD]

Be sure you get any dead fish or other animals out of the tank asap. Your tank does not seem to be cycled. Please see my response to your other post.

FWIW, I think emerald crabs are generally okay, I've even kept them with seahorses. Five chromis in a 55 is a lot. They don't seem to school like people think, and usually get reduced to one or two by aggression.

Once things get settled, we can help you get your tank stocked. With a 55 gallon tank, you aren't going to be able to keep that many fish, so you need to think through what you want, reconciling it with the realities of fish hardiness, compatibility, and adult size. Are you going to keep a reef tank or a Fish Only with Live Rock (FOWLR)? Either way, people here can help you out. Just take it slow in the future.

Good luck!

 

[RicksReefs]

your chromis likely have a bacterial infection.
lately, most newly imported green chromis have it.

the crabs were just cleaning up.

 

[Slakker]

Don't put anything else in your tank until your ammonia and nitrite are ZERO, these are both VERY toxic to fish and are certainly not helping your chromis survive.

 

[unbreakable]

^^ yes, dont add anything until your tank has finished cycling. You shouldn't have nitrite or ammonia in your tank

 

["Umm fish?"]

I agree that the emerald was probably just cleaning up already dead fish. Any nitrite or ammonia is a bad thing.

That said, I have seen an emerald taking swipes at fish as they swam by. It might have just been a defensive posture, but I got it out of there in a hurry.

 

[wordwarrior]

I have serious doubts that the Emerald Crab is killing your fish. They are basically scavengers and they'll generally only go after a meal - such as snails - if you are not feeding your tank. I have several of them in my 90 and one in the 30 and they've never bothered anything that wasn't already dead.

 

[OneRobertG]

Some have seen my other post but the Chromis were already dead. Maybe the emeralds aren't so bad after all. 11AM can't come soon enough so I can change this water.

I'm going to talk to the LFS owner and see how the other Chromis are. Mine were happy as a pig in pooh when I put them in the tank, immediately playing in the flow generator and eating.

 

[tbar]

It's not uncommon for Green Chromis to kill each other off till only the strongest couple are left. Usually within the first couple of days of purchase. In a tank your size that is most likely want happened and naturally the crabs would then do what crabs do.

 

[OneRobertG]

tbar...well I do have 2 now and they both seem to be healthy so maybe they did kill each other off. I never saw them being aggressive toward each other though. I think I let the chemistry get too far out of whack. LFS talked me into buying too many fish too soon. LFS has about 20 in a tank which is about 1/4 the size of mine and they all look good so I think my tank is not established enough for the fish I had. I was trying to go slow but the LFS owner was pushing me.

Anyhow I think the case is closed, the emeralds didn't have anything to do with killing the fish.

 

[wordwarrior]

Find an lfs that has a staff/management you can depend on for correct information and sound advice about stocking levels etc... Hopefully you're not from too small a town in the usa and have access to more than one or two shops. Good luck - be sure to talk to the store about your incident - it may encourage them to be more careful when selling goods to new, or relatively new, aquarium owners.