30 C is around 85 degrees F, so make sure your fish can handle that. If thats too hot, just go as high as you can. Your fry should be fine. My molly had fry and the conditions were far less than ideal with doing water changes and such. If they grow up with different conditions, they will usually do well with anything. You can buy ich medication from just about any pet store that sells fish stuff. kevkoi gave good advice saying the remedy should have malachite green. Good luck!

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-Kat