Pervasive tetra fin rot?

April 4, 2011 8:58 PM

What can I do about my tetras' chronic fin rot?

About a year ago I adopted a fish tank from a friend of mine who was moving out of town. Here are the specifications:

- 29 gallon freshwater tank
- Way overpowered Emperor biowheel filter
- Gravel Substrate
- Flourescent light on a twelve hour cycle
- Water chemistry is stable at 0ppm ammonia, 0ppm nitrites and <20ppm nitrates

The tank is stocked with:

- Four pearl gouramis
- Two black-skirted tetras
- Four neon tetras.

At the beginning of my ownership I managed to kill a fair amount of guppies, but I believe that was due to my inexperience and overfeeding.

My problem at the moment (or annoyance, more like) is that all of the tetras suffer from seemingly aggressive fin rot. Here are some photos:

Black-skirted tetra
Neon tetra

They all seemed to have this amount of damage when I received them, and their condition has not worsened since I've had them in my care. The gouramis in the tank don't show any signs of fin rot or other disease whatsoever. About two weeks ago, one of the black tetras developed a tail-fin infection (white nodules and decaying tissue) which ate away at its tail and then died down. About six months ago I tried a course of antibiotics (tetracycline) but it didn't seem to do anything.

So my question is, what, if anything, can I do about the tattered fins on these fish? They don't seem to be suffering really, and certainly aren't terminal, but I feel like a fairly crappy fishkeeper because they don't seem to be able to get back to a state of optimum health. Is this simply a matter of poor genetics or something like that?

Any thoughts would be appreciated.

posted by mmcg to pets & animals (5 answers total)

The second photo is actually of longfinned Serpae Tetra (Hyphessobrycon eques), not neon tetras.

Tetras are committed fin nippers (which is why the development of long-finned variants is madness), generally the only cure is a larger tank or heavy planting to give the victims a place to hide.
posted by jamaro at 9:13 PM on April 4, 2011

Sorry, yes, they are serpaes and not neons. My mistake; one should not drink Dogfish 60 Minute and ask for aquarium advice.
posted by mmcg at 9:19 PM on April 4, 2011

Yeah I don't think this is fin rot dude. The serpaes (we call that specific serpae a 'black phantom' in Aus) are eating everyone's fins. I've had this happen a lot. Some people seem to do well with serpae's but in my experience they were relentlessly aggressive pains in the arse.

Sub them out and put in more black-skirted/black widows if that's the look you like.
posted by smoke at 9:25 PM on April 4, 2011

Also, the fins being nipped away is totally irritating to the fish, but typically not fatal. The aggressive pestering and harassment that goes with the nipping may very well be, however. Stressed fish are sick fish.
posted by smoke at 9:28 PM on April 4, 2011

I would actually blame the gouramis. I've kept gouramis many times over the years, and they've always been agressive fin nippers. Gouramis are mean little bastards in a community tank (at least all the tanks I've had). Got so bad the last time, that I had to return the gouramis to the store after they ate the fins down to nubs on my barbs and mollies. Jerks even hassled the pleco. Keep a close eye on them, you'll probably see fish chasing each other around and "herding" each other around the tank. The chasers are the culprits.
posted by cuddles.mcsnuggy at 8:36 AM on April 5, 2011