I acquired 4 young platies (about 3 cm long) and put them with my Betta some days ago. Today, I have seen one of the platies showing some sort of shiny white with a rainbow glare (like oil on the surface of water) on the upper half of his body and and though his overall mood looks fine, he is eating less than the others. My betta doesn't look different in appearance, but his fins are starting to get clamped.
Given the description it seems to me that velvet is the cause and I want to treat the fish before it gets worse. I read copper sulfate is an effective treatment but some fish are sensitive to it. Do you know if Bettas or Platies can tolerate copper? Which is the recommended concentration (on copper basis) for treatment? I have access to reactive grade copper sulfate and I can prepare the solution on my own.
Info about my tank.
Size: 10 gal
Temperature: 26 ºC, with a heater.
Filter: Elite Stingray 10
Aeration: half of an Elite air pump for 20 gal with a valve to lower the turbulence.
Community: four small platies and a male Veil Tail.
Food: for platies, Tetra Min or Tetra color (although my Betta actually likes those flakes!)
For Memín (the betta), betta pellets, freeze dried bloodworms and ocasional live Daphnias and brine shrimp.
I feed the platies twice a day and Memín once a day.
Plants: two Elodea.
Water change: 50 % capacity twice a week because the filter isn't probably fully cycled (I do vacuum the gravel, which acumulates sunken flakes).
Additives to water: BettaSafe for chlorine, an additive for plants (mostly oligoelements and iron), a low concentration of aquarium salt and a little of a pH reducer (the active agent being phosphoric acid) to bring the pH to about 7,2).
Water parameters: I haven't been able to get aquarium water testers so I ignore nitrogen parameters on my tank. I know the following parameters on my water because I happen to work at the lab that performs the tests:
Hardness:169,19 mg CaCO3 / L
Calcium hardness: 135 mg CaCO3 / L
Alkalinity:190 mg CaCO3 / L
Yes, now I know I should have quarantined the new fish. I will have the ammonia tested soon.