Mysterious Parasite

[andee619]

Hi guys. I would like to ask if anyone here keeping Otocinclus has experience dealing with their parasites?

Five days ago I bought 5 Otos and joined my main tank 3 days later. During feeding I noticed that one of the otos has a lump below its mouth. I immediately removed the oto from my tank and examined the lump. I came up with the conclusion that the lump is cystic so I decided to perform a small surgery to open the cyst to at least relieve my fish of suffering. I was shocked to see the "cyst" content slowly unfolds. It was actually a flat worm. After I cleaned the wound I transferred my oto in a quarantine tank with antihelminthic solution hoping to eradicate any remaining parasites. Currently my fish is still doing well very active and eating. The worm is currently preserved pending identification.

Unfortunately the other 4 otos were already dead and never had a chance to perform postmortem exam so I don't know what possibly could have caused the death. Am still thinking whether to treat the whole tank as the tank's main inhabitants are my corys.

Any catfish keepers who has the same experience?

Thanks.

[stormhawk]

This is the first time I'm hearing of flat worms on a freshwater fish. Typically what you find is fish louse aka Argulus. These parasites do not kill the fish but weaken it, so it's likely that your Otos died of other causes. Were they skinny when you bought them? Emaciated Otos do not live very long, especially those kept in improper conditions at the LFS.

[andee619]

This is the first time I'm hearing of flat worms on a freshwater fish. Typically what you find is fish louse aka Argulus. These parasites do not kill the fish but weaken it, so it's likely that your Otos died of other causes. Were they skinny when you bought them? Emaciated Otos do not live very long, especially those kept in improper conditions at the LFS.

Hi! Thanks for your response. I am sure its not Argulus. I also can not believe it when the parasite unfolded and started swimming on the water. What made me purchased the Otos is their appearance. They were very fat and bigger than the usual ones that we see from our LFS. I actually wanted to get more but the shop got only 5 pcs left on their tank.

To date, the infected Oto is nearing completion of the treatment. Two more days and he can already join my main tank. The wound is completely healed and appetite is very good (can finish 1/4 hikari algae wafer in one feeding). So far no sign of infection outbreak in my main tank. Unfotunately he is the only survivor, the rest of the batch RIP.

In retrospect I should have administered prophylactic treatment with the rest of the batch. I learned a lot from this experience. I will update this post once identity of the worm is confirmed.