Goldfish buoyancy issues/spinal deformity?
Approximate 4 year old goldfish, previously in 55G tank with 5 other siblings fish. Approx 3 weeks ago, he began having difficulty maintaining buoyancy, and would struggle to swim vertically to the surface then sink repeatedly. Appears to have misshaped body/disfigurement to lower spine?
Tried peas and salt baths in hospital tank to address swim bladder issues. QT tank has bio filter and bubble stone. Water parameters and temperature normal.
Had mild discoloration of fins, treated with melafix then on to kanaplex and metroplex, with appropriate timing for doses and water changes.
Meds remedied fin appearance but the behavior and buoyancy has not improved. Sits on bottom of tank, staring into the corner, flutters up on occasion, still attempts to eat.
Any suggestions or ideas as to cause? Thank you!