SERPAE TETRA

Question
I HAVE A LARGE SCHOOL OF SERPAE TETRA, SEVEN OF WHICH ARE LONG FIN AND FANCY.  ? TWO OF THESE FANCY ARE SWIMMING ON THERE SIDE, DOING A KIND OF JERK-SWIM.  THE ARE OTHERWISE FINE. THEY DO SWIM UPRIGHT WHILE BEING FED.  NO OTHER SYMPTOM.  WHAT IF ANYTHING CAN I DO ???  ALL TANK COND. ARE GOOD,  ALL MAINTENANCE IS BEING DONE.  NOTHING HAS CHANGED IN THE ROUTINE. HELP!

KEITH

Answer
It sounds like they have some internal parasite. This means they need to be treated. It sounds like bloat or a bladder condition. Either way, it would be best to get an all-in-one treatment for internal parasites. Treat them following the directions exactly, including the water changes and dose. It would be best if you could remove the sick fish to a hospital tank but if this is not possible treat anyways. Keep a close eye on the fish to see if changes develop or if any other fish develop something. I hope this helps. Let me know if you need anything else.