I know this all sounds like overkill, but when it comes to biosecurity and preventing cross-contamination, there is no such thing as overkill. I basically treat the whole situation of QT as if anything and everything associated with the new fish is contaminated, so therefore I want it coming into contact with nothing else. Do you know the saying “treated like they have the plague”? Well, that is what you should really do. If the fish are simply fish from the ponds here at the farm, which is the case most often) the protocol remains the same. However, there will be no bags and boxes involved in these cases. Instead we bring them in the building in tanks, and net them into their prospective systems. The fish from each individual pond should be put in individual systems. This so as not to have fish from multiple ponds in the same tanks. All nets, tubs, buckets, etc. shall be kept from cross contaminating other systems, and shall be immediately disinfected after use.
At this point, fill out that system log statistics, including the source of the fish (breeder, dealer etc.), date released into the system, and any treatment immediately utilized, as well as any noted symptoms or pathogens observed upon release. If they are foreign fish, the exact source/breeder/dealer they came from should be recorded. Make sure not to mix fish from multiple breeders/dealers in the same system. Each source should have their own separate QT and equipment. Also note and record all water parameters tested in that system. I would even suggest the hobbyist keep these records as well, and test and record water parameters on a daily basis. Unless emergency treatments are immediately necessary, let the fish remain untreated (other than salt) for a period of one to two days after arrival. I prefer two days of rest if it is possible. During these two days however, a salt addition of one part per thousand per day can and should be added, starting with the first day, and daily for two days, until a two parts per thousand (.2%) level is reached on the second day. Higher salt concentrations (up to six parts per thousand) may be utilized for certain approved circumstances, but these levels must be achieved with only .1% additions per day. If these higher doses are required, you may need to bring them back down to no higher than .2% prior to certain other treatments that contain Formalin and malachite green combinations. Some folks have speculated that the fish have had bad reactions to the salt and F&MG combination. We will discuss this later as well. It is important to understand however that we only go to the higher levels of salt above .2% for specific reasons such as increasing slime coat and to aid with cases of fish with dropsy. (Bulging eyes and/or scales standing out like a pinecone, and/or ulcerations)
Fish should be fed minimally, if at all during the treatment protocol. I primarily only feed a little just to see if they eat or not. Whether a fish eats or not can be a good indicator of their well being and health. Sometimes however, they may simply be too frightened to eat, so it is important to understand this as well. Food that is new to the fish can also cause them not to eat at times. Maintaining good water quality is far more important than feeding, and in many cases here at the farm we are starting with a freshly sterilized system with very little biological activity in the filtration. This is why daily water testing is also critical.
After the appropriate resting period, and no later than the second day after arrival, a microscopy of at least 10% of the fish in that batch shall be done. In some cases where new fish exhibit symptoms of parasites as soon as they arrive, they may need to be treated on the first day, so in these cases the microscopy would have to be immediately upon arrival. As for immediate treatments, this is a little tricky, and not often needed. In most cases you need to let the fish rest from the stress of shipping and a new environment.
When doing the microscopy, each fish of the 10% chosen in each batch will be separately scraped and scoped from multiple areas, and gill snips must also be done and scoped as well. We will discuss microscopy for the hobbyist at a later time. Also in speaking of hobbyist, there are times that you may get fish from a dealer or breeder that has already treated them, and there will be no need for further treatments. Microscopy would verify this. If you do a microscopy, and find no parasites, then I would not do any treatments. However, here at the farm (or any farm for that matter) it is rare that any fish coming from the mud ponds do not have any parasites, and therefore at least some of the following treatments protocols will usually be required. Once the microscopy is done, record any pathogens noted in the log for that system. Here at the farm, the most common parasites seen are protozoan, and of these Trichodina is the most common. We will see the occasional