Hi, Jenn and all - we have, I think, got the same problem, and I don't know how or why. Pippin had finrot which we had thought healed - he was missing a chunk from his bottom fin, but Deirdre saw no redness, and it didn't seem to be progressing. She had treated it with bettafix. Tonight, when we came back from our long weekend, we both saw that his dorsal fin was red and ragged. Poor little guy! He doesn't seem uncomfortable, and he's swimming and eating well, but it looks just awful. Deirdre was pretty upset, and I told her I'd post to the board. We took the carbon out of the filter, she did a 30 percent water change, and we began bettamax. His situation:

6 gallon eclipse tank and filter. One 10 month old betta (Pippin), and a small female ancistrus (Luna Lovegood). The tank is pretty much maxed out - 5 inches of fish in there. Deirdre has an anubias barteri on driftwood, java ferns, 3 river pebbles, and two or three plastic plants in an inch-deep layer of dark gravel. Also a lot of java moss on the bottom. The moss is getting choked with algae, but Luna keeps after the algae on the rest of the plants and fixtures. They have a heater - it's set to between 78 and 80 - and Deirdre does a 30 percent water change about every 14 days.

When we tested the water today, there was no ammonia, no nitrite, nitrates about 20 ppm, pH 7.5. All perfectly normal. Deirdre thinks, even though the water seems pretty clean, she should perhaps do a change weekly since she has the two fish in there? Other possible stressors: Pip doesn't especially like the current, though Deirdre tries to break it up with the plants. And, though the fish are peaceful enough together (they generally ignore each other), they are not exactly friends. Pip tries to steal Luna's algae wafer every evening, and she chases him off. Could she be nipping him, and, if so, what can we do about it? Is there anything else we can do?
What should we be looking for?

TIA for your help!

Oh Boy - More Finrot! What in the ### is going on???

I guess she can step up the water changes if she wants to but your params are perfect so... I can only say that water changes stress out one of my bettas so... I'd just keep an eye on it if she decides to do it.

I had to change filter types for my poor guy - he just needs almost no current at all (but a bowl causes too much ammonia & then the rot gets bad and so on....) I'm not sure how you'd handle that with an eclipse. Toothless told me to try putting more plants on top of the water while still leaving pockets for Bubba to come up for air.

I'm sorry I have no experience with keeping other fish with my betta. Hopefully someone will come along for that soon!!!

Hope this helps,

Jenn

Thanks, Jenn!

(This is Deirdre, writing on Mary's account).
I was thinking the water changes might actually be stressing him a little, because the weather is getting a lot cooler now, and the heat hasn't come on very strongly in my apartment building yet. So, although I have a heater, the temperature in the tank drops when I change the water. (Because room temperature is lower than it used to be....)

Do you think this could be part of the problem?

Anyway, I'll keep treating him & trying to keep the tank very clean. I also thought I might try warming my bottles of clean water in the kitchen sink before adding them to the tank.

Thanks for all your help. You're great!

Deirdre (& Pippin & Luna Lovegood)

PS. Rubeus is still doing great, btw!