Bad news, woke up to a dead angelfish
I just tested my water the day before, all parameters were normal except nitrates which were at 40ppm.
I didn't think to test the water they came in, I've never done that before. I just let their bag float for 30mins then let them go, the other fish is doing great :/
You got the floating the bag part right
but you did nothing to adjust the fish to the new water.
In the future, you want to float for 15-30 mins depending on the amount of water in the bag, ( More water equals longer float time) then add a small amount of water every 10-15 minutes until the majority of the water in the bag is more new water than the water the fish came in. ( If you are uncertain, it is okay to dump some of the water out of the bag then repeat the adding water part until the fish look like they are okay in the new water.)
Here's a hint: when you take the fish out of the bag and put it/them in the tank ( use a wet net for this), save the water you acclimated them in. If they show signs of too much stress in the tank, you can put them back into their old water and reacclimate them more slowly. ( This would better be done in a bucket with a drip system. )
As stated before, it is never a good idea to add the bag water back into the tank (even after acclimating.) You see, water in the bag can turn foul during transport so you are not doing your tank any favors by adding it back to the tank. Also, as stated before, you don't know what was in the water the fish came from (you should read some of the threads and posts on this site about quarantining new fish and why you should) so you definitely don't want to add anything to your system.
FYI: Just because some fish are able to adjust to rapid water changes does not mean that they all will. You just had that experience. HOWEVER, a weaker fish, if acclimated properly, has a good chance of surviving the change. (BTW: rapid change is a common cause for ich breakouts. Watch these new fish for any signs of irritation.)
Keeping fish is a learning experience. You just learned a lesson.
Carry that lesson forward to all your future fish purchases and you should eliminate a lot of future problems
lastly: it is better to have the store test their water in front of you than to test the water in the bag with the fish. As previously stated, water with fish in it can be altered by their breathing and eliminations. These are temporary changes. You want to know what the fish were living in so that they looked and acted good enough for you to want to buy them.
Hope this helps
