What fish can I keep in a 5 gallon coldwater tank?
Non of those fish are suitable for a 5 gallon tank. Zebra Danios are sub-tropical very very active fish, they need to be in shoals in at least a 2ft long aquarium or larger. Rummy Nose Tetras are tropical, preferring high end tropical, can be very sensitive to water quality and need at least a 25-30 gallon tank for a shoal. Platys are tropical fish and need at least a 12-15 gallon tank, not a 5 gallon at all. White Clouds are sub-tropical fish that need a very highly oxygenated tank. For a shoal you need at least a 10-15 gallon tank, not a 5 gallon. Green Barbs – I presume you mean Green Tiger Barbs? These are tropical fish which get to a chunky 2.5″, you need at least a 30g for a shoal and they can be real terrors, they should be kept in groups over 8-10. Ruby Barbs also get to a very chunky 2.5″ and I wouldn’t really recommend a shoal of these for any smaller than 20 gallons. In short, none of the fish you have mentioned are suitable for that size tank. All I’d recommend for a 5 gall
