You ask several questions. I'll try to answer each.
Although you say the Shop has done some treatment I don't know exactly what they did. I mean, what was and is the concentrations of Praziquantel and Copper they used? Sorry to reply with a question, but not knowing these it is hard to give recommendations. I will say this: Most local marine fish stores (LMFSs)
don't run therapeutic levels of copper. I've not heard of any shop running Praziquantel in addition to copper. However, most likely this would not be therapeutic levels of this medicine either.
Most LMFSs just want to hold back any diseases that might show up before they sell the fish. If this is the case, then you need to consider they haven't performed any actual treatment and the fish will need to be kept in QT and treated.
WATCH OUT. Some wrasses are sensitive to copper. I'm not sure your wrasses can handle therapeutic levels of copper.
You need to choose which copper product you want to use. If you choose to use Cupramine, the therapeutic level is 0.05 copper. If you plan on using Copper Power, the therapeutic level is 2.5 ppm. You
must purchase and use the
Hanna Low Level Copper Test Kit to measure copper. This is the most precise and easiest to use test kit. It takes all the subjectivity (guesswork) from testing for copper.
If the Shop has been putting Praziquantel into their system and keeps it there then they have made a
BIG MISTAKE. Praziquantel has an issue where it becomes less effective each time it is used. A species of bacteria grows in the tank that eats prazi as a food source. Each time it Is used, the bacteria grows more and gets better at eating it. After three treatments, it is consuming the prazi almost as fast as it is added. So after a couple of weeks of using Praziquantel in the Shop's system, it is worthless -- the Shop is just feeding the bacteria. So, using Praziquantel in your QT should be okay. Here's one plan:
If you choose to use Cupramine, you can dose Praziquantel at the same time.
If you choose to use Copper Power you first threat with this; then after this treatment you treat with Praziquantel. Use
This Addition Calculator or Copper Power.
If you trust the Shop performed a proper Praziquantel treatment/dip initially, then no need to treat with PraziPro.
This would be my advice. Watch them. BUT do treat with PraziPro as directed on the package. AND go ahead and buy the copper of your choice AND the
Hanna Copper Test Kit. You need to have these on hand and part of your 'fish medicine cabinet.'
I would have thought there was a QT procedure here on this site. . .somewhere. I can write one up if it's needed, but it is a lot of work and I don't want to duplicate something that is already posted.
Lastly I can recommend reading the
Fish Nutrition Post for feeding recommendations.
Ask if you have more questions.