Red thread mark on albino senegal?

[Tharissa]

Hi folks,

I've been planning for a couple years for a pair of senegal bichirs; did the research (most of it from here! grateful for all the amazing folks sharing their knowledge), seeded a cannister with media from my other tank, got the tank set up and cycled weeks ahead of their arrival. I'm religious about water changes and testing (my tap water reads .25 ammonia, so i have to be), parameters are all 0--I haven't seen nitrates since I added floating plants (pre-fish arrival). They're in a 55 gallon, sole other creature in the tank is a nerrite snail. The only thing remarkable going on is that my tap has a fairly high ph, usually 8.2ish. I drip acclimated them *very* slowly because of this.

A few weeks after I got them, the bigger grey fish showed a sort of pale patch of scales on his back:
I assumed some kind of parasite and treated the tank with praziquantel, and the patch was gone in a few days.

About 3 weeks later, the other bichir very suddenly showed a red thread on his fin and overnight his tail had gone rather ragged:


I asked for advice in another forum, confirmed that all my water parameters were still 0, and treated with aquarium salts (heaping tbsp/5gal) and erythromycin on the assumption that something bacterial was going on. I've been on the lookout for aggression or nipping, sometimes the grey will nose the albino but I haven't seen a nip. The tail has been healing, but yesterday I found yet another red thread-like streak on a different fin:


Can anybody shed light on what I'm missing or how I should treat this going forward? I really appreciate the assistance. Thanks! <3

 

[Rocksor]

put a divider u in between them . aggression can happen with lights out.

 

[Tharissa]

put a divider u in between them . aggression can happen with lights out.

Thank you! I'll do so.

 

[clm08k]

As Rocksor said, It looks like aggression or fin nipping to me. That can result in jagged fins with small flecks of red( particularly in the lines or on the finlets).
If the albino is the smallest one in the tank, it might be getting picked on. If it is just the two, then you might need more of a group to try and displace the aggression. If the bigger one was added first as the lone bichir in the tank, it might be territorial.

The divider can definitely work. I've used an egg crate (light diffuser) in the past with separating some of my fish. You can buy this at a hardware store like Home Depot/Lowes, etc.


P.S. Sounds like you are doing a great job managing the water parameters. That sounds really hard with keeping the ammonia down. It sounds like you are handling though. Good luck! Also that albino is a cutie!

 

[Tharissa]

Thanks so much! I've had the divider up & kept up with salt, and the albino is looking much better! I'm waiting for the final bits of his tail to heal and then i'll reintroduce them (hopefully the length/bulk he has put on will help even them out?). If it's still troublesome I'll consider some more tank mates. Are there any dither fishes that wont get immediately eaten?

I really appreciate everybody's help with this. While I've got you, do you have a clear idea on the sex of this one? I've been saying "he" but from the diagrams I've seen I wonder if I have it wrong!