Rasbora got attacked!

[Luananeko]

I found one of my Narrow-Wedge Rasbora bleeding and swimming upside down tonight... I have him in a floating isolation chamber at the moment and he's laying on his back right now. I think it would take a miracle for him to survive at this point, so I'm just trying to figure out what happened... I've listed the likely culprits from my stock list below...

1 male King betta (4" or so) - one of the originals in the tank, has been full grown for a while and always been super mellow and never even flared at the rasboras and tetras
4 Trichogaster trichopterus gourami (4" or so, 1 male, 3 females, various color morphs)
1 Pearl gourami (4") - not sure gender... male maybe, has some red on the throat, but not as bright as the pics I've seen of males
1 Red Tail Black Shark juvie (3") - always seems oblivious to the other tank mates

The gourami were added about a week ago and I have been watching them closely. They chase each other on occasion, but nothing serious. None of them have shown any interest whatsoever in the rasboras before now, and the previous inhabitants had been getting along peachy for months. The betta doesn't even bother the gourami or even the male guppies that are also in the tank. He flares at the gourami occasionally, but never chases them or bites at them. Just puts on a show and follows them slowly (like Pepe le Pew ) until they leave his area.

Any ideas? Is this a fluke accident, or something more serious? My current guess is that the rasbora got in the middle of one of the periodic gourami turf chases, but the rasbora looks way too beaten up for that... If I have to I'd rather take back the rest of the rasbora school than any of the ones on the list above, even though I've had the rasboras for ages.

Edit: The tank is a 75 gallon heavily planted community tank that gets 50% water changes weekly.

 

[Jesselav1233]

My guess would be the gouramis I've had a lot of them over the years because I think they look awesome but I've definitely had them bite/terrorize other fish usually they just chase each other around but I've had them attack other tank mates as well. It's to bad cause like I said I love their colors but they seem kinda simple minded as far as fish go.

 

[Samzter]

I would say the shark and Gouramis , although I've never had trouble with mine, but most people are unfortunate when it comes to them

 

[Luananeko]

I'm thinking it was the gourami as well... But do you think this is going to be a chronic issue, or was it a fluke? Should I rehome the rasboras?

 

[Jesselav1233]

I'm thinking it was the gourami as well... But do you think this is going to be a chronic issue, or was it a fluke? Should I rehome the rasboras?

Honestly I've had a lot of gouramis and once they show aggression they usually are relentless to whatever they bully. You could try taking him out and putting him in another tank for a few weeks and try reintroducing him later on that might help him be less territorial but that's prob a long shot

 

[Luananeko]

Honestly I've had a lot of gouramis and once they show aggression they usually are relentless to whatever they bully. You could try taking him out and putting him in another tank for a few weeks and try reintroducing him later on that might help him be less territorial but that's prob a long shot

Thats the thing, I have no idea which gourami may have done it since I've never seen any of them even look at the rasboras before... So I'm not sure which one I would isolate. Even when they practically swim right into the rasbora school, they don't seem to pay them any mind. I've been watching them like a hawk for the last day to see if I can tell who it might have been, but haven't seen any sign of aggression outside of the periodic turf chases with the other gourami.

 

[Jesselav1233]

Thats the thing, I have no idea which gourami may have done it since I've never seen any of them even look at the rasboras before... So I'm not sure which one I would isolate. Even when they practically swim right into the rasbora school, they don't seem to pay them any mind. I've been watching them like a hawk for the last day to see if I can tell who it might have been, but haven't seen any sign of aggression outside of the periodic turf chases with the other gourami.

Huh u would prob see them chasing the others if it was him in my experience they never were very subtle about it usually relentless attacking when it would happen

 

[Luananeko]

Still no sign of any more aggression... I apparently lost another rasbora before this one was attacked. I did a head count when this one was hurt and couldn't find my 6th rasbora, but I was hoping that was because of all the plants and hidey holes the fish have to hide in, combined with the fact that I can't tell the rasboras apart and have trouble counting them while they're all swimming. But still no sign of him now 3 days later.

The remaining 4 are still looking happy, stress free, and no signs of bullying, so I think maybe I lost one rasbora to some fluke thing, and then the second one got in the way of a gourami chase... They're small enough compared to the gourami that a couple bites probably could do the damage I saw. I'll keep watching how everyone gets on before deciding whether to rehome the remaining school or not. They tend to school with my black neon tetras (never would have guessed), so they should be fine numbers-wise for the next month while I watch to make sure there's no repeat... If no issues then I'll look into topping their school back off.