The difference between ich and velvet?

[RedParrotBubbles85]

Well some of the fish in my 55 gallon tank have come down with a case of ich. i treated it all went well and the ich was gone. then the next day loads of white "spots" are back on the same fish. the tank is 55 gallons with 2 jacks who dont have anything, 2 blue acaras who have it, 2 convicts who do not have it, a foremouth who doesnt have it, and a bala shark who has got it really bad. i am still treating for ich, but could it be velvet that i have and am mistreating the fish for ich? most of the more dominant fish have nothing wrong with them, but the less agressice fish seem very succeptable to it. sorry i have not tested, but i know the water is good as i did a 50% water change on Saturday and raised the temp to 81 degrees. please help me. thanks a lot.

[chc]

Both will respond to formalin/malachite green combinations (Qucik Cure, etc.). That's one of the best, yet most stressful, options out there.

Even though some of the fish don't show signs of infection, they probably are (or at least they're carrying). If you eradicate the parasites completely, it cannot return unless you itroduce an infected organism. People will tell you ich, etc. is always in the system, but that's simply not true. Yes, it may hide unseen in the gills of fish, but once it's eradicated it's gone.

Now, most fish are fairly resistant to ich and other diseases. I suspect either you recently introduced organisms or your water quality dropped a bit. You need to look at long term solutions to eliminate that (i.e. use of quarantine tanks, stepped up water changes, improved filtration, etc.). Immediately, though, you'll need to treat the fish.

You'll hear lots of advice: salt, high temperatures, etc. Forget about those and just go with Quick Cure. Change a lot of the water in your tank now (75% or so) and filter overnight through PolyFIlter or a very good carbon to remove any remaining medication. Remove the PolyFilter or Carbon and treat with Quick Cure. In spite of what the directions say, treat only every other day unless you're going to change 90% of the water before a new treatment. There are only two stages in the life cycle of ich when it can be killed, and I won't bore you with the details, but keep medicating for at least a week. If it were me, I'd change water before every treatment, and I'd vacuum the gravel well each time (the litter critters live in an on all decorations).

Just a warning, the shark may not stand the medicine well. Either treat him in another tank or be willing to lose him if he's already doing poorly. Smooth skinned fish don't handle the formalin/mal. green mix well.

I'd feed lightly through the process, and I woulnd't worry about raising the temperature too high (82 or so is fine). If the tank isn't already aerated well, you may want to add an airstone. Most importantly, treat for at least a week.