Elimination: Very important!!!
4. Well you did your best, but those little buggers got ich anyway (darn them!). Mistake numer one: raise the temperature. What if your fish are temperature stressed to begin with (no, they won't tell you...)? Ok, stay with me here, the end will justify the means. When you raise the temperature in your tank, two things happen. The most well known is that the life cycle of ich increases! Yay! Well, to kill ich, you have to catch it in its free swimming form (called "theronts"
. That's great. The more theronts exposed to medication, the better. Or is it? At this stage, we are only thinking about killing the ich, and we are blinded to how our prized fish are really doing. This leads us to the second thing that happens: the dissolved oxygen content is reduced! Additionally, the metabolic rate of our fish increases! A higher metabolic rate causes our fish to consume more of the oxygen in the wat...wait a minute...didn't we just reduce the oxygen content in the water? Remember from earlier I told you that the first place ich infests is the gills? Not only have we decreased the amount of oxygen in the water, we've increased our fishs' consumption of oxygen, and our fish definitely have ich infestations on their gills! This is why we should not increase the water temperature. There is no reason why medication cannot take care of this problem with a stable water temperature (provided you use the correct medication, see #6).
5. Mistake number 2 is to add salt. What excactly is salt doing FOR your fish? It doesn't kill ich. Nor is it a disinfectant. Salt is a very poor excuse for proper prevention or medication. When you go to the doctor, he doesn't prescribe you salt for infections does he? It is in fact possible that the reliance upon salt has resulted in more fish losses than the disease itself. Salt can be useful in about two certain circumstances (treatment of nitrite poisoning and osmoregulatory stress), but not for the treatment of ich. I can go on and on about why salt is bad, but I will just mention one more thing: salt is an irritant to tetras, catfish, goldfish, and koi.
6. What is a proper medication for ich? Very simple: malachite green, formalin, or a mixture of the two. Copper is another, but it is lethal to freshwater fish. So, when treating, remember that scaless fish (tetras, catfish, loaches, etc.) are very sensitive to medications, and the amount should be reduced to half the recommended dose. I have treated loaches many times, and they are free of ich (obvious infestations) in 3-4 days using the formalin/malachite green mix. Most other fish are "cured" in less that time. Treating longer is better, but this mix is a bit rough on live plants. Half dose twice daily (with activated carbon filtration, once daily without) works really well.
Good luck on your next tank, and school your mom on your fishes! Who knows, she may actually get interested!