Can Congo Tetras be aggressive? - Fish for the Planted Aquarium

Jeanine · 07-25-2009, 05:36 AM

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.

Karebear · 07-25-2009, 05:52 AM

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".

Jeanine · 07-25-2009, 09:12 AM

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.

Jeanine · 07-25-2009, 09:26 AM

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!

amphirion · 07-27-2009, 09:48 PM

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.

tranr · 07-27-2009, 10:28 PM

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.

armedbiggiet · 07-31-2009, 12:43 AM

Quote:

Originally Posted by Karebear

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.

dawntwister · 08-05-2009, 11:23 AM

Quote:

Originally Posted by Jeanine

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?

Jeanine · 10-17-2009, 09:48 AM

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?

Tex Gal · 10-17-2009, 01:21 PM

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.