Holy Cow...parasites, now with pictures...

[Polypterus]

It is not unusual for leeches to come in on water hyacynths which are usually pond grown. One treatment for leeches in koi ponds recommended Trichlorofon

Dylox (Trichlorofon) is a medication that should be used as a dip, it should not be added to a tank to get rid of harmless critters....I would question it's use in this manner and especially with catfish in the tank.

This stuff is quite toxic and should not be used for just anything...

 

[rjmtx]

If the leeches aren't on the fish, they won't be, and I wouldn't worry about it. The amphipods aren't really a problem, either. I'd just look at it as free fish food. They probably came in on the plants.

 

[TheBloodyIrish]

Most leeches are not parasites... only a few of them are. They are pretty obvious if they are parasites though. I like them though, they keep my vivariums nice and clean of nasties.

 

[FishGoneWild]

That's some sick looking stuffs in the pics!