I have to say, without a doubt, that my favorite piece of tank equipment is my UV sterilizer/powerhead. I haven't seen much mention of UV sterilizers within the forums and wanted to get a feel if other members have had luck treating their fish with it and to raise awareness of its benefits in an aquarium.
I got my sterilizer because I was getting clown loaches and keep hearing horror stories about how susceptible they are to disease, especially ich. I used to have major problems keeping newly purchased neon tetras alive for more than a day or two, but after adding the sterilizer I have not lost a single tetra and have been able to build up my school to about 15. I don't know if the sterilizer makes for better water conditions and less stress for easier acclimation or if it maybe helps eliminate any parasites they may normally carry in from the petstore.
Also, yy molly developed tiny black spots on her body and fin (looked like black grains of sand or a black ich) so I put the UV sterilizer back into the tank and did a water change and within 30 hours she was clear of any black spots.
This post has been a bit rambling, but I hope that people with a persistent problem of disease in their tank or those who just can't seem to cure their favorite fish of that mysterious disease will now have another option to try: UV sterilizers.