Sterazin is the best thing for gill flukes, I would have suggested Myxazin as well as I had a very similar disease sweep though my tank unfortunately - Have to admit I have never heard of eye flukes... its more likely just cloudy eye which is a bacterial disease caused by stress which can come either as water quality or a result of a bad disease/ parasite infest.
Just as a side note (not 100% sure how it will be greeted but...) even though that tank is quite large by some standards I dont think it will last the Sharks their full life - especially when they are a big group up at the 10-12 inch mark swarming around it like crazy. The saving grace with these monsters is that they are very very common so these in your friends tank will have a much better life than a very large percentage of those in the hobby in the world. I have a similar sized tank and it is hard not to put big big fish in it but you sometimes just have to limit the max size a little less than you would think that it would perhaps be okay.
Wills
Just as a side note (not 100% sure how it will be greeted but...) even though that tank is quite large by some standards I dont think it will last the Sharks their full life - especially when they are a big group up at the 10-12 inch mark swarming around it like crazy. The saving grace with these monsters is that they are very very common so these in your friends tank will have a much better life than a very large percentage of those in the hobby in the world. I have a similar sized tank and it is hard not to put big big fish in it but you sometimes just have to limit the max size a little less than you would think that it would perhaps be okay.
Wills
