Bully Fish

[Wells]

Hello all, I've had my tank running for awhile now, and started with a small school of Harlequin Rasboras. After I acclimated them to the new tank and released, I noticed one had no eyes from the store but thought I would see how he/she goes.

They've been in there for about 3 weeks now, and I added a further 3 to increase school size to 9, the blind fish has adapted well for survival and spends his time, a little sadly, alone bottom-dwelling to find food. It's a decent amount planted tank and his been fine, however one of the fish from the school has recently now been swimming out of his way to find Noah ( the only fish I can actually identify cos of the eyes lol) and attacking/fin slapping him. I added a guppy today as well, and he seems to be showing signs of aggression towards him as well, chasing mainly.

I'm not really sure what I should do about it, do I remove the trouble fish, remove Noah or just leave them be?

Tank is a fluval flex 57l, hard water if that info is needed.

 

[ClownLurch]

Bigger shoal?
Tank divider or breeding net for poor Noah? His own little tank?

 

[Byron]

Don't separate the loner, this will only make it worse and add more stress. Fish communicate via chemical signals, pheromones that others in the species can read, and allomones that other species read. Visual (eye) communication is obviously normally important, but the chemical signals are as well, particularly here.

I'm wondering if the interaction is actually gender-related, or pre-spawning interactions? This suggests itself by terms like "fin slapping."

 

[squidneh]

I have Harlequin Rasboras (12) and they have been more aggressive towards one another now that they are trying to spawn (unsuccessfully as I believe my water is a bit too hard). Mine are extremely active and I see a few of them pairing off and having an argument now and then throughout the day.

So it could be normal or they could be taking advantage of the fish's weakness but either way I agree it is probably best to leave it be. I have one who came from the store with 1 eye, and she is lucky enough that she lives a totally normal life.

 

[Retired Viking]

I have Harlequin Rasboras (12) and they have been more aggressive towards one another now that they are trying to spawn (unsuccessfully as I believe my water is a bit too hard). Mine are extremely active and I see a few of them pairing off and having an argument now and then throughout the day.

So it could be normal or they could be taking advantage of the fish's weakness but either way I agree it is probably best to leave it be. I have one who came from the store with 1 eye, and she is lucky enough that she lives a totally normal life.

You could try adding RO water to reduce your water's hardness if you want fry. That is what I have been doing with my tetras. My red eyed tetra have had several fry over several months that grew to adulthood. 14 total fry stating out with just 5 adults.