betta death mystery

My beautiful blue betta fish died on Saturday. I'm so very sad. His name was Blue. I've decided not to replace him at this time. However, when I went to clean out the 2.5-gallon aquarium I noticed a black soot-like substance near the filtering unit on the sides of the aquarium and on the unit...

My daughter got a betta for her 8th birthday a few months ago and she has been doing a GREAT job taking care of it she always remembered to feed it and if she wasn't home she called to ask someone else to feed it she was careful to avoid overfeeding! After doing a little research I decided to...

Hello, I am new to fish keeping, and this was my first fish. I bought a betta fish from petsmart two weeks ago. I bought one that looked very colorful and active. I put him in a 5 gallon tank, with a heater and a filter. I treated my tap water with declorinater and chemical remover first, and...

My old fish died but I never knew why, I didn't do anything different to it's environment,

Okay, so my betta Johnny who used to be so happy suddenly died. I had thought that he killed himself because I found him under his decorative bridge, and I thought he got stuck and drowned...but strangely when I pulled the bridge off, I saw this HUGE black dot on poor Johnny's lung. It looked...