White and slimey coating on roots of Java fern

[bernie]

A few of my Java Fern on DW have developed these white & slimey coating around the rhizome area. What are these and are they harmful to fish? Will it cause ammonia spike etc?

Should I clean it up or can leave it as it is?

[stormhawk]

It is probably a colony of some macroscopic animal, probably a freshwater bryozoan or just plain old fungus. I would probably clean it if I was you. It will not cause an ammonia spike but may affect your fish if they attempt to eat it. The slime may affect your filter bacteria as well, so it's best to scrub it off if you can.

[bernie]

Thanks for the reply. Will clean it as I have fries in it.

[stormhawk]

You're welcome. Sometimes the fry may peck at the bryozoans (if that's what they are) but usually they leave it alone. Then again, better not to leave things to chance, if the fry are important.