I think this is a Great information because my tank was great till this weekend i changed my gravel and when i did that i used a rag i had laying around the house and my wife after all was said and done told me it might have been used with comet and ever since then they have been swimming low and high weak as well. so i put them in a 35 gallon q tank and will be chaning the water 80 percent again today, thx. will keep u posted.