Petco Text Logo
Petco Pet Logo

What's the white cotton stuff in my fish tank and how do I remove it?

Updated On September 23rd, 2025

My new fish tank is being occupied by some white cotton web like thing at the bottom.. the are found on the natural plants and food remainings in the tank.. please help .. how to get rid of it? I tried changing the water 3 times..

1 Answer

Most Helpful Answer

Image profile

Answered By Todd Cecil

Veterinarian

Published on November 14th, 2018

Thanks for reaching out. This problem is perplexing, but possibilities include fungal or bacterial overgrowths. A good cleaning might help to alleviate your problems. Continue to test water quality and correct problems. Sometimes the over-growth of anaerobic bacteria (those which grow in low or no oxygen conditions, at the bottom of the tank), can form strange formations of detritus. Submitting a sample to a lab might help determine an answer. Good luck.

Vote icon

1Pet Parents found this answer helpful

image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Sponsored