My hippo tang was the only fish in a tank where I used Ivomec 1% @ 4ml per 30 gal (for a week before a partial water change) and it showed no ill effects. I would guess that it may be safe for most fish but since there is some uncertainty, I would be prepared to either remove the fish if they become stressed or be prepared for a major water change. This would be another reason to experiment with dosages to see if you can get by with a much lower dosage. I wouldn't be surprised if my relatively low dosage (4ml/30 gal) used over an extended period of time (3-4 weeks) would be good enough to eliminate them. If it was me, I might consider starting with that dosage in the main tank and adding more if it isn't effective after a couple of days. (Or, again, experiment with lower dosages with bathes first to find a reasonable "starting dosage"). This plan could possibly work if it is true that the half-life is as long as @sculpin01 mentioned. I never looked into its half-life so that is new info for me, and this can work to our favor since that may allow you to gradually increase the concentration over a period of time (without previous dosings breaking down).I haven’t tried interceptor, I’m still waiting on my order from Canada. Once I get the interceptor I’ll give it a shot.
Will ivermectin kill the fish?