These spectacular fish (Pseudanthias species) are tropical marine (salt water) fish.
no tropical fish need warm water
No. Tropical Fish required warmer water.
No! because tropical fish live in heated water and koi in cold water.
There are a couple of things you can do to control the pH of the water for tropical fish. You can for example drain the water and start over.
"Tropical" simply means the aquarium is kept above 60F. "Marine" simply means the water in the aquarium has had sea salt added to make the water into sea water. Therefore it is possible to have aquaria that are "Tropical", or "Marine", and also "Tropical marine".
Those are salt-water tropical fish not the freshwater fish you see in pet-stores.
NO do not put tropical and marine fish together because marine fish have salt water that has to have specific things in it other Wise they will die .but tropical fish just have to have warm water with a heater .you cant mix these together because of the water and ALL your fish will DIE.
None, goldfish are cold water fish, so having a tropical fish as a tank-mate just wouldn't work because tropical fish need to live in warm water.
Fresh Water
Whether or not a tropical fish can survive in cloudy water depends on why the water is cloudy. If there has been a spike in ammonia or nitrates, it can be deadly to fish. Tropical species tend to be more sensitive to severe water changes than freshwater fish.
These fish like warm water