This is what I could find on the subject in
this thread. Never done it but the description below is pretty detailed. Hope it helps
The short version:
- 5 minute freshwater dip
- Immediately afterwards, perform a chemical bath (in saltwater matching SG/temp the fish came from). You have two options:
- Acriflavine (preferred) - Do the bath for 75-90 minutes, but remove the fish immediately at the first sign of distress. Aerate heavily both before & during the bath, and temperature control the water. The following products contain acriflavine: Acriflavine-MS and Ruby Reef Rally. DO NOT mix acriflavine with any other chemicals.
- Formalin - Do the bath for 30-60 minutes max, but remove the fish immediately at the first sign of distress. Aerate heavily both before & during the bath, and temperature control the water. The following products contain formalin: Formalin-MS, Quick Cure, Aquarium Solutions Ich-X, Kordon Rid-Ich Plus. Use protection (rubber gloves, face mask, eye protection, etc.) whenever handling formalin as it is a known carcinogen! However, you can add Methylene Blue to the formalin bath (1 capful per 2-3 gallons of bath water.)
- After the bath, place the fish in a QT pre-dosed at 80mg/gal using Chloroquine phosphate. In theory, copper (exs. Cupramine, Coppersafe, Copper Power) should work just as well as CP. However, due to how fast velvet can reproduce you don’t have the luxury of slowly ramping up the copper level as is normally advised. Therefore, the fish needs to be placed in a QT with copper already at minimum therapeutic levels. This is the advantage CP has over copper in this particular situation.
- While in QT, use a wide spectrum antibiotic (exs. Seachem Kanaplex, Furan-2) for the first week to ward off any possible bacterial infections. Secondary bacterial infections are very common in fish with preexisting parasitic infestations such as velvet.
- Keep the fish in CP or copper (at therapeutic levels) for one month. However, you can transfer the fish into a non-medicated holding tank for observation after just two weeks (explained below). DO NOT lower the CP or copper level before transferring.
The long-winded version:
I’d like to explain in more detail about what the above mentioned treatments accomplish:
Freshwater dip - This is very useful for removing most of the “surface parasites”. Noga (2000) and Noga & Levy (1995) both reported that a single freshwater dip would remove 80-90% of the parasites. I thought that would be enough to move on to copper or CP in a QT. However, the fish I treated with just a freshwater dip and then in-tank QT treatment continually died. Therefore I came to the conclusion a chemical bath was also needed before being moved into QT treatment (see below). Here is how you perform a freshwater dip:
Fill a bucket with RODI water, and use a heater to match the temperature to the water the fish is coming from. Aerate the water heavily for at least 30 minutes prior to doing the dip, then discontinue aeration while performing the dip. Fish aren’t overly pH sensitive for short durations like this, but you can squirt a little tank water into the dip just before the fish goes in to help bring it up.
Place the fish in the freshwater (FW) dip and observe closely. It is not unusual for them to freak out a little at first. Also, tangs are notorious for “playing dead” during a FW dip. The important thing is to watch their gills; they should be breathing heavily at all times during the dip. If breathing slows, it’s time to exit the dip. Dip the fish for no longer than 5 minutes.
Some fish can have an adverse reaction to a FW dip by appearing unable to maintain their equilibrium once returned to the aquarium. If this happens, hold the fish upright (using latex, nitrile or rubber gloves), and gently glide him through the water (to get saltwater flowing through the gills again). It is also a good idea to place the fish in an acclimation box until he appears “normal.”
Acriflavine - This is a new drug (to me anyway), but it seems to have a lot of potential as a replacement for formalin. It has a broad range of effect, being effective against both protozoans and bacterial infections. The latter gives it an advantage over using formalin, because all those tiny bite marks inflicted by velvet have the potential to get infected. You can also leave a fish in acriflavine longer than formalin, because it is not as harsh on the fish. Dosage varies by the product you are using, but for straight acriflavine (
Acriflavine-MS) use 1 teaspoon per 5 gallons of water for a bath solution.