# fin nipping problems?



## dorabaker (Jul 3, 2010)

A couple of days ago i added 7 glowlight tetras to my tank. I already had a gourami and 4 cherry barbs and they seemed to be getting along ok with each other, but this morning when i woke up every one of the barbs had ragged edges to their tail fins, and i noticed that the glowlights were pecking them. the glowlights appear to peck each other a fair a bit (i noticed this behaviour in the LFS), but don't seem to do each other any harm. but the barbs seem a bit stressed out by the fin nipping, and there are only 4 of them against 7 tetras.
i'm not sure what to do about this. I guess it could settle down eventually because they are new fish and sometimes there's some tension until they settle in, but isn't it usually the established fish that peck the new fish, not the other way round? :-?
anyway, what i'm wondering is, what can i do about this problem? would getting a couple more cherry barbs make the existing ones feel safer and more able to stand up to the tetras? i have 11 small shoaling fish altogether and my 15 gallon tank is looking quite crowded already, and i also intend to get a couple of corys later on, so i wasn't planning to get any more barbs. but if it wasn't going to add too much to the bioload and it'd make the barbs happier, i'd get some more. what's your opinion? please help :|


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## Byron (Mar 7, 2009)

I think I warned of this a while back. Please take this criticism in the spirit it is being offered, out of genuine concern for the fish.

A 15g is too small a tank for this mix of fish. Glowlights are peaceful, _very_ peaceful. But any shoaling fish placed in a small (to them) confined space, or in insufficient numbers [7 is fine in this respect], become stressed, and frustrated, and they lash out about the only way they can--taking it out on everything else. This sort of behaviourial response is common among many animals, and humans too for that matter.

The cherry barbs will be highly stressed by just having the tetra in the tank. Fish release chemical signals, pheromones, and other fish read them. Even if no physical harm occurred, in this situation the barbs would be almost petrified by the presence of the tetra who are obviuosly sending out signals. In this case there is also the physical proof.

In a 15g or 20g high, which both have the same surface footprint, only one group of shoaling fish of the "average" sized species is possible, and then provided they are not active swimmers which would require more length, say a 20g long. Going with the "dwarf" species is much better, as you can have more of them in terms of species and numbers of each species.

I would not expect things to improve. Fish that become aggitated and stressed to this degree usually do not go back to being peaceful, unless they are moved to a completely different and larger tank. At least in my experience.

Byron.


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## dorabaker (Jul 3, 2010)

Byron said:


> I think I warned of this a while back. Please take this criticism in the spirit it is being offered, out of genuine concern for the fish.
> 
> A 15g is too small a tank for this mix of fish. Glowlights are peaceful, _very_ peaceful. But any shoaling fish placed in a small (to them) confined space, or in insufficient numbers [7 is fine in this respect], become stressed, and frustrated, and they lash out about the only way they can--taking it out on everything else. This sort of behaviourial response is common among many animals, and humans too for that matter.
> 
> ...


actually i'm pretty sure nobody on this site has told me that it isn't a good idea to mix different species of shoaling fish in a tank the size of mine :-? otherwise i wouldn't have got the glowlights. what do you mean by 'dwarf' species?


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## Byron (Mar 7, 2009)

dorabaker said:


> actually i'm pretty sure nobody on this site has told me that it isn't a good idea to mix different species of shoaling fish in a tank the size of mine :-? otherwise i wouldn't have got the glowlights. what do you mean by 'dwarf' species?


I may have been thinking of another thread, there have been several lately on this issue. The advice still stands though.

The "common" tetra, rasbora, etc. like glowlights, neons, harlequin rasbora and such attain 1.5 to 2 inches. The "dwarf" species rarely exceed 1 inch. Among the tetra, Ember Tetra is in our profiles. Among rasbora, any of the Boraras species like Boraras brigittae in our profiles, and the Emerald Dwarf Rasbora, Scarlet Badis, Celestial Pearl Danio are all in the profiles. Subject to water parameters (as some of these are soft, others hard) these can be combined nicely in a 15g or 20g tank, 7-8 of each species, 3-4 species, plus some substrate fish. It allows for more fish in a small space, which means more interest for the aquarist.

There are some other fish too, like the sparkling gourami; Dicrossus filamentosus among the dwarf cichlids will work. Then there are some of the pencilfish that do well because they are not active swimmers. And one of the hatchetfish species from Carnegiella. Quite a few options.

I have three "large" tanks, but some of my finest enjoyment is to sit in front of the 10g and observe the several fish species; small fish get "lost" in large tanks.


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## dorabaker (Jul 3, 2010)

thanks 
i'm a bit worried that the cherry barbs are going to get fin rot, so i'm treating the tank with some melafix for a week. i don't know that i even believe in that stuff, but then i've never used it to treat fin rot before, only mystery fish illnesses that may well have not been curable anyway. the barbs are acting as lively as ever so i'm not too worried, but melafix is meant to help with healing fins and stuff so i thought it would be a good idea.


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