Most of those fish you mentioned are tropical species and require higher temperatures.
I wouldn't recommend putting them in that tank with those fish, they can go in with fish but only small docile species - mine are in beside some white cloud mountain minnows - both are suited to the similar temperatures and they are really lovely calm fish that won't hassle the newts - depending on the size some may get eaten by the newts, but mine have been in together for a couple of months now and haven't lost any fish yet and both the fish and the newts have been much more active and healthy looking since as well!
so if you want to have fish and newts in the same tank, only use small docile fish like these - you could probably get away with danios or even guppies but given they require a higher temperature than the newts the white cloud mountain minnows are a much better choice
Clouded mountain minnows are one of the only suitable fish to be put with newts. It is not because they are docile, its because they are quick and unlikely to get eaten and do not produce as much ammonia as some other species. The other fish you mention are likely to get eaten and for example guppies would be happier in higher temperature than the newts.
I have 3 CFBNs and 2 blue tailed fire belly newts in with a fighting fish,1 Striped Raphael Catfish and one yellow sucking fish.I know the Striped Raphael Catfish is bigger than my newts but they seem to get along just fine,although my newts occasionally 'kick out' the Striped Raphael from his hiding place so they can have it :lol2:
Your fish are tropical species and require higher temperatures than a CFBN should ever have to stand. You must either be keeping the fish at a too low temperature or the newt in too high temperature. Either way you are likely to make the animals ill, keeping them at the wrong temperature.
I cannot stress more the importance of doing your research for the species you keep, especially if you have a community tank.
For newts, remember in the wild they would be in a much bigger environment, so being stuck in a smaller environment in captivity putting them with fish may put them under unnecessary stress and provide unrealistic conditions and situations.
Regarding temperature: Keeping newts at too high temperature increases the chance of them getting things like bloat as their immune system works better at lower temperatures. Keeping fish at too low temperature increases the chance of them getting things like white spot, as again their bodies are not able to function as well.
