What happened to their tails??

[nlifs]

Hello,

Another day, another question about my aquarium!

Woke up this morning to find one of my cardinal tetras completely missing his tail (picture #1) ... needless to say, he didn't make it. Then I noticed another one with a severe tail injury (picture #2).



The other tank mates are:

6 furcata rainbowfish (been in the tank for almost a week and had not previously caused any harm, although they are somewhat hyperactive)

1 onion nerite snail (added yesterday)

2 honey gouramis, one male and one femaile (also added yesterday)

The only suspect I can think of is the (male) gourami ... but I was told that these were peaceful community fish?? Could he have bitten off the cardinals' tails? If so, why? And how do I prevent it from happening to the other cardinals?

Any help would be greatly appreciated.

 

[nlifs]

Related question - should I try to get some Melafix for the injured tetra?

 

[Andy Sager]

I would point more towards the rainbowfish than the Gourami. The dead Cardinal also has a very shrunken in belly which could have made him weak and that's a key sign for other fish to eat them. As for the treating the other one with a missing tail, you would need to treat that in another tank with an antibiotic to keep it from getting worse. Which one would depend on your water parameters. FYI: There is very little proof that those " holistic" meds Melafix and Primafix actually do any good as a curative. They may do okay as a preventative but there is some concern about using them with anabantids ( Gouramis, Bettas, Labrynth fish species ).

 

[nlifs]

OK, thanks. I don't have another tank so I guess that's a 'no' on the treatment. Any chance he gets better on his own? He's fairly large, on par with the rainbowfish, so I'm surprised they're biting him ... the LFS knew that I had some cardinals; surprised that they recommended these other guys ...

Anything I can do to reduce further aggression? Now that I'm thinking about it, the rainbowfish do seem to gobble up most of the food and the cardinals stay hidden in their corner most of the time ... probably intimidated by them.

Would love to hear any suggestions for restoring some peace and harmony ...

 

[Andy Sager]

OK, thanks. I don't have another tank so I guess that's a 'no' on the treatment. Any chance he gets better on his own? He's fairly large, on par with the rainbowfish, so I'm surprised they're biting him ... the LFS knew that I had some cardinals; surprised that they recommended these other guys ...

Anything I can do to reduce further aggression? Now that I'm thinking about it, the rainbowfish do seem to gobble up most of the food and the cardinals stay hidden in their corner most of the time ... probably intimidated by them.

Would love to hear any suggestions for restoring some peace and harmony ...

You can try feeding them more often. Just use smaller amounts of food per feeding. Full bellies should make them less aggressive. You may need to put food on both sides of the tank if the cardinals are coming to the surface or you'll need to blow some food down to the bottom of the tank in the area of the cardinals while the rainbows are fed at the surface. I like to use a turkey baster for doing this.

 

[nlifs]

More aggression

Woke up this morning to find another cardinal with severe fin damage ...

In the picture, the fish on the right is fine, the one in the middle had his tailfin almost completely destroyed yesterday, and the one on the left has significant damage ... Somehow they're all still swimming.

I was told these forktails were 'peaceful' and good community fish

I did feed them last night ... even gave them a treat (frozen daphnia) but apparently they still feel the need to nip at my poor little cardinals.

As mentioned, I don't have another tank to move the cardinals to. Anything else I can do to try and reduce this aggression?

Any suggestions would be greatly appreciated as usual.

 

[Aiken Drum]

Put a divider in the tank? Keep one group one side, the other on the other?

Add some more plants and bigger pieces of aquascape to break up lines of sight more?

I think generally your fish are considered a good mix, but every group is different and some fish are just jerks no matter what you do. Ultimately i dont think your fish will able to cohabit.

 

[nlifs]

Thank you for the suggestions!

I'm watching them now and it looks like one of the rainbowfish, in particular, is quite aggressive. He's hanging around one side of the aquarium and scaring away any fish (even his own 'brethren') that dare to venture nearby ...

Is this normal behaviour? He also seems to be darting around a little more quickly/violently than the other fish.

 

[Andy Sager]

Put a divider in the tank? Keep one group one side, the other on the other?

Add some more plants and bigger pieces of aquascape to break up lines of sight more?

I think generally your fish are considered a good mix, but every group is different and some fish are just jerks no matter what you do. Ultimately i dont think your fish will able to cohabit.

What Aiken said.

If you can post a video of this behavior, hopefully we can tell if this is not a disease darting vs an aggressive behavior.
It's possible that you have a dominant male ( a.k.a. The Jerk ) and a sub dominant male ( a.k.a. the victim) which would make this behavior normal.