Good Or Bad Idea :a :l?

[Spishkey]

cardinals here vary from €0,50 to a euro depending on size

 

[rdd1952]

...I'd say that stocking is waaaay to much for a 66 Gallon.

Actually, 200l is about 50 gallons. I would agree that the tank is already overstocked.

As for the original question, yes, I think adding 50 cardinals at once could quite possibly too much bioload addition at once. Discus need great water conditions so you certainly don't want to do anything that suddenly shoots the ammonia, nitrite and nitrate up. The more stock in a discus tank, the more rigid you maintenance schedule will need to be.

Certainly one more serious issue is do you have a Q-tank to put them in for 2 to 4 weeks? If you have a healthy tank of fish, you certainly don't want to introduce 50 potential disease carrying fish into the tank.

And last but not least, I agree with Davo that the BGK will most likely feast on the cardinals. Expensive feeders.