sick tiger barb

[saara824]

I have a 30 gallon tank with a koi angelfish, 4 livebearers, a large pleco and 2 tiger barbs. The green tiger barb is lethargic, appears to be twitchy and struggling to stay afloat. He was so healthy before. Was unsure if I had ick so I raised the temp and added the blue stuff. He started eatting again but the twitchiness(sp) is still there. Has anyone experienced this before? Can anybody help me. I don't want him to die. He is so pretty. Thanks