Micro Rasboras Picking At Betta's Tail?

[trianglekitty]

My betta shares his 10 gallon tank with seven mirco rasboras (Chila rasboras) and three mini moth catfish. He's been very good about leaving the other fish alone.

Today I noticed his back fin has been torn. A small section of the top half of the fin is actually missing. It doesn't look like fin rot or anything like that. I've never seen the rasboras interact with him in anyway, but is it possible they're pecking at him? The only other thing I can think of would be that he somehow got his fin caught in the filter intake.

Which of these two theories (rasboras or filter intake) seem more likely?

 

[BigTom]

I'd be very surprised if the rasboras were to blame, although I guess it isn't impossible. More likely he just snagged it on something.

 

[Fishy friend2]

I agree with the above post. I would doubt that the issue was the micro rasboras, typically they don't nip in numbers higher than six unless they feel insecure due to minimal cover. There could be a wider range of potential possibilities, it could even be a result of too much flow, lots of long finned bettas have delicate fins and too much flow can easily rip them, along with plastic plants, tail biting, and catching there fins on something sharp such as a decoration.

Your tank is a bit over stocked. I wouldn't necessarily recommend to remove the fish but you have very sensitive fish, and are known to perish on even the slightest of undesirable conditions. I would recommend staying on top of waer quality and dong more than the required water change amount for the amount lfs ammonia being produced, probably around x2 weekly water changes of around 25-30%

 

[trianglekitty]

I agree with the above post. I would doubt that the issue was the micro rasboras, typically they don't nip in numbers higher than six unless they feel insecure due to minimal cover. There could be a wider range of potential possibilities, it could even be a result of too much flow, lots of long finned bettas have delicate fins and too much flow can easily rip them, along with plastic plants, tail biting, and catching there fins on something sharp such as a decoration.

Your tank is a bit over stocked. I wouldn't necessarily recommend to remove the fish but you have very sensitive fish, and are known to perish on even the slightest of undesirable conditions. I would recommend staying on top of waer quality and dong more than the required water change amount for the amount lfs ammonia being produced, probably around x2 weekly water changes of around 25-30%

That's already what I do. I do a 30% water change on Wednesdays and Sundays and test daily in-between using the API liquid test kit. I've had the rasboras and cats for several months now with no issues at all (and the rasboras have colored up beautifully!). The tank is heavily planted with live plants (so no plastic to catch fins). There's a coconut cave and a temple for the cat fish to hide in, but they don't have any edges...everything is smooth curves. I have floss in front of the filter outlet to keep the flow down for the betta (and use a bubble wand to keep the O2 levels up for the catfish)

The only thing I can think other than the rasboras (which I agree seems unlikely) is that he somehow got caught in the intake for the filter. Is there anything I can do to prevent that from happening again? Maybe wrapping some stocking material around the filter intake?

 

[Fishy friend2]

Usually from getting caught in the intake of the filter, it effects the whole fin and not just one area, another possibility if tailbiting if he is a long finned Betta