why do you need hardy fish if the tanks fully cycled and mature? most fish will be fine in a mature tank with hard water just introduce them slowly.
cause i am sick to death of adding fish like neons and rams and they die even though my tanks has been running for a long while and is fully matured and i test my water every 2-3 days with api freshwater test kit and it always comes up fine and i keep up my water changes every week, and some fish are still to sensitive to put in thats why i am looking for a good hardy fish that i can keep in there untill its lifespan is over.
what are your water parameters? if its way off the lfs's then slow long acclimatisation will be needed to get the fish used to your water
well tbh i just put the bag in the water for 5 mins and then cut it open i only do this because i get my fish from a pet shop about 18 miles away and the water loses heat over that journey even though i wrap the fish bags in paper and then put in a poly box with a lid it keeps the heat in
this could be your problem. in 18 miles water can vary quite a bit, birmingham is about 20 ish miles from me and they have very soft water and mine is quite hard. i would float the bag for about 10 minutes to get the water inside up to temp then gently add small amounts of water from your tank into the bag, i use a syringe and add about 30ml every 5 or 10 minutes for about 30 - 40 minutes then using a net get the fish out of the bag and into your tank. i would never add lfs water to any of my tanks not even my quarentine tank as you never know whats in it..... there is a maidenhead near me about 6-7 miles away and they use filtered water and have a pH of about 6 in their tanks, out the tap mines about Ph 7.5-8. there are many things that can vary in water not just pH so its always best to acclimatise them slowly and take your time as the fish will be stressed out enough without just being thrown into completely different water parameters
