It had a sponge filter on it so not the HOB
. Its only about a year old & I did a water change on it yesterday & didn't notice anything off so I don't know. The airline has a one way valve on it so the water doesn't back flow to the pump & the pump was still running when I got home. The tank has always had a very slight bow so maybe one of the "joints" finally loosened up a little too much (?). The snails & male Betta are OK, the Betta is floating in a Tupperware bowl in the 46g because my 2 extra tanks are currently being used as hospital tanks so I guess I'll be hitting up Petsmart on my lunch tomorrow.