At 02:11 PM 5/15/97 +0000, you wrote: >I'm having a weird illness amongst my juvenile Ap. agassizii which >I think resembles Hole in the head. The symptoms are a protruding, Sorry to hear about your case of HTH syndrome Fredrik. I too am having a similar problem in my 100 gallon community tank with my Gymnogeophagus balzanii adults.(3 left) It's mainly a South American tank with Apistos, Corydoras, some Black Skirts, Gold Zebra Danios, Leopard Danios, Madagascar Rainbows, Herbertaxelrodi Rainbows, Turquoise Rainbows, Silvertip Tetras, Black Neons, Kribs and some Angels, and of course the balzanii (of which are the largest animal in the tank and a trio of Corydoras pygmaeus are the smallest).I had another problem that had arose and sent a question to the Editor of the Apisto-Gram, the official newsletter for the Apistogramma Study Group, which is world wide. He forwarded it to "The Fish Doc." and I was told to use formaldehyde on the other problem. I goofed. I used 3 tablespoons instead of 3 teaspoons and instead of leaving the fish in the container for no more than 50 minutes, they were in there for 1 1/2 hours! The dip cured the other problem it was meant for. It also helped a bit for the HTH. The one white spot on his forhead (because of the treatment), erupted and it looked like what ever it was cured that one. The only fish that appear to be affected are the balzanii. I'm continuing the treatment tomorrow, as directed this time, and hopefully it will help. It has definitely slowed it down. Try some of the formaldehyde. I will be sending another "letter" to "The Fish Doc" and will let you know the results unless someone else out there already has an answer. I hope this helped. Kaycy djhanson@pop.calweb.com