# Can Congo Tetras be aggressive?



## Jeanine (Apr 4, 2009)

I recently bought 5 Harlequin's and they all seemed pretty healthy. I found one dead a few days ago that was partially eaten. Since then 2 more have mysteriously disappeared. I don't see any bodies in there and I haven't noticed any sick fish. Other than the Congo's the only other fish I have in there are 2 neon tetras, 1 headlight tetra, 3 oto's and one Cory. Oh yes, and a Rainbow shark that I haven't seen in 3 weeks since I moved. My tank is quite heavily planted. I've looked through the plants, but haven't seen any bodies. Oh yes, I also have 2 or 3 amano shrimp that I don't see either. My husband and I feed the Congos large flies and have seen how well they rip those apart, and they love snacking on the plants. Could they be getting a taste for fellow tank mates? I feed the fish once a day.


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## Karebear (Oct 6, 2008)

How long ago did you get the harlequins? If it has been less than a week, it could be moving stress to the fish store. I would finger the rainbow shark as the bad guy before the congo tetras, they can get pretty aggressive, however if the congo's are larger and the harlequins fit in thier mouth they can eat them. Rule of thumb is: "if it can fit in the mouth, it will fit in the mouth".


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## Jeanine (Apr 4, 2009)

I got the harlequins about a week ago. I just checked and am down to one lonely harlequin now. Last night before bed I checked and there were 2 left. Both were doing fine, swimming and eating, no sign of illness. There are no bodies in the tank and none on the floor (there is a one inch gap at the back). I haven't seen the rainbow shark in almost 3 weeks, and I've been working in the tank pruning and replanting plants. Weird, no body. At first I thought he was hiding because of the move. It's almost like there is a time portal in the tank and fish are just falling into it and into space. I can't figure it out. The congo's are doing fine though.


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## Jeanine (Apr 4, 2009)

Well, I just dropped in a tubeflex worm cube ( the fish love those things) and who should magically appear from the great void, but, Rainbow Shark. Gosh he sure looks good, nice round belly from his holiday. I guess he's been eating well............... perhaps to well? funny thing how a fish can hide like that!


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## amphirion (Nov 13, 2008)

yes. i recall one of my female congos trying to take a bite out of a rummy nose. took her out of the tank and placed her in another--the rummynose failed to survive the ordeal.


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## tranr (May 20, 2009)

This is slightly off-topic from your original thread - sorry about that. I don't know how big your tank is, so I am not certain if you can introduce more fish, but some of your tetras would probably benefit from being in schools of their own kind (groups of 6 or more). Neon tetras definitely like to be in schools (they will school with cardinal tetras), as do the corydoras sp. typically. I'd recommend getting a few more neons, headlights, and corys - they'll probably be happier for it.


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## armedbiggiet (May 6, 2006)

Karebear said:


> How long ago did you get the harlequins? If it has been less than a week, it could be moving stress to the fish store. I would finger the rainbow shark as the bad guy before the congo tetras, they can get pretty aggressive, however if the congo's are larger and the harlequins fit in thier mouth they can eat them. Rule of thumb is: "if it can fit in the mouth, it will fit in the mouth".


But there are neons right? why the congo did not go after the neon? To me I just think Harlequins are not that easy to keep since they sometime die for no reason. Ask the fish store next time how long have they been in there store, maybe they are stress out like Karebear said.


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## dawntwister (Sep 29, 2007)

Jeanine said:


> I recently bought 5 Harlequin's. Other than the Congo's the only other fish I have in there are 2 neon tetras, 1 headlight tetra, 3 oto's and one Cory. Oh yes, and a Rainbow shark


What size tank is this? Is there a link to a picture?


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## Jeanine (Apr 4, 2009)

I have a 55 gallon tank. I would like to have a few schools (Harlequin and Neons), but it seems to me, that every time I get new fish, they "disappear". I have a feeling that the Rainbow Shark is the culprit. How long do they live for?


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## Tex Gal (Nov 1, 2007)

Why not trade the rainbow shark for something else? It's a shame to have such a big tank and have one fish control it. If he were in a bigger tank with other rainbow sharks or big fish he'd be kept in check somewhat.


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## Six (May 29, 2006)

I'd definitely look at the congos first in regard to eating tankmates. Especially if you add a new fish to their tank- they're going to think you're feeding them when you put the new fish in. They may be aggressive in that situation and cause damage or stress to the new fish. Stressed fish can equal dead fish pretty easily. Or the new fish may not have been the best from the store. If my fish die in a week, I get a little wary of the store's batch and maybe go back to look if they also had some die off. 
Were the congos introduced after the neons? I agree, if the neons were introduced while the congos were in the tank they'd be a good lunch for the congos- or would get chased and stressed quite a bit. 
Also, if a fish is dead in the tank, the other fish will definitely eat them no matter what species they are. That's just fish. The r'bow is probably eating the remains first since he's the scavenger of the tank.

I;d choose between having a semi-aggressive community tank (congos, r'bow shark) OR peaceful community (neons, small rasbora, etc) and add fish that fit into those. 

GL!


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## Jeanine (Apr 4, 2009)

Here is a picture of my tank. It is a 55 gallon. I recently did some major pruning because there was no room for the fish to swim. Plants were literally growing out of the water.
I would like to go with smaller tetras. The Congos were a disappointment because I got them when they were very small, and thought I would get about half male. As it ended up I only got 1 male out of the 6. He's very beautiful. The recluse rainbow shark still rules the bottom of the tank, and I may have to put up with him until spring.
Thank you all for your advice.


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## Six (May 29, 2006)

heck, id be happy with that many females- i like to breed my fishes though... hehe. on the good side, that male is probably very happy!


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