Update. Fish are still lying on the bottom. 1 of my dither fish is dead. An Australian rainbowfish. I had 4 in total. I am doing a 50% water change and added an airstone to see if this helps at all. Not looking good at this point. Might have to pull out the new sump tonight if things don't improve.
Also the rest of my Rainbowfish. The Cubans are hanging on barely as well as the Salvini. Did massive water change and removed new sump. Will continue water changes tomorrow and run only my cannister for now. I guess even after 30 years of keeping fish you can still learn a few things. Have attached a picture of the silicone used and the sump. Tomorrow I start over and will use GE Silicone I clear. I have used all kinds of silicones over the years and never had this happen. Still can't believe this was the problem but can see nothing else. I would love to hear from people who say they have used this with no problems. I need sleep so will continue this tomorrow.
