My air stones in my tank kept getting knocked loose by my cats. When i grabbed em to burry them back under the gravel they crumbled in my hands. Being that i didnt have any more air stones i just took the tubes out since they were blowing huge loud obnoxious bubbles. I figured the fish would be ok until i could run to petsmart the next morning. that was 10:00pm.... 5:0am wake up to take the dog out and go into to check on my fish. All dead. My 18in RTC, 12in Cichla Mono, 14in TSN, 14 in Niger, and 14in RTCxTSN... the only survivors were the two ugly ass gold fish.