Help! Fish dying!

[Justfishin17]

Hey everyone! So my tank has been up and running for almost 6 months now. I'm just starting to come out of having a diatom problem. Everything has been going great for a couple weeks. Then, all of a sudden I lost a red platy. I checked my temp, water parameters, and filter and everything was fine. I did a water change just in case. Then another week later I lost another platy. Again checked everything and it all looked great but I did a water change just in case. Just hours after the water change I lost an otocinculous. Anybody have insight as to what is going on?

 

[bnpleco]

Could be many things an internal parasite the fish are old or they just died

 

[marsh]

More details might help. Gallons? Stock list?

 

[Justfishin17]

My fish are no more than 6 months old all were bought young. I've got 2 tiger barbs, 2 albino tiger barbs, 1 green barb, 3 roseline sharks, 2 otocinculous, 2 flying foxes, and 2 plecos in a 55gallon tank. I've lost 3 fish in less than 12 hours

 

[bigbanker]

Barbs are known to bully fish to death. If your parameters are "fine" the barbs may be the problem or something (oils or sprays) may have gotten in the tank.

 

[Justfishin17]

My barbs are schooled and leave everything alone. I haven't sprayed anything around or near the tank recently.

 

[bigbanker]

I used to keep 15 tigers despite the group size they still bullied everything

 

[Justfishin17]

It's not my tigers. Some of my tigers have died. I Sid several large water changes and for the last 3 days I haven't had a dead fish. Any thoughts?