I need help to identify what appears to be leeches in my tank and after I find out what they are would like to know if they are harmful to my fish and how to get rid of them if they are.
The tank is 90L (UK) and has been set up for over 2 years now.
I have a Zigzag Eel, Senegal Bichir, Banjo Catfish and possibly 2 Armoured Shrimp (they are good at hiding so can't say for sure) in the tank.
The "leeches" are between 2 and 6 millimeters, they are a light grey colour, also i have noticed some have a small white patch on the underside. I'm afraid I can't get any pictures just yet as I scraped them off the glass when I first noticed them they usually come out when my tank gets a bit dirty and I done a water change a couple of days ago. The easiest way I can think to describe their shape is that they resemble bowling pins with the neck being skinny and the body and head oval shaped.
I don't buy alot of fish anymore but I do get plants from time to time as they don't last very long, so the most likely place they came from is the sponge that is used to protect the plant roots.
I know there's not alot to work with but any info or suggestions what they might be would be appreciated, I will go check my tank now and see if I can get a pic to help.