• A freswater aquarium: Tap water or bottled water?Aquarium image by crossgolfing from Fotolia.com
  
  

Tap Water Unsafe

• Municipal tap water can be unsafe to use in a fish tank if it is highly chlorinated or contaminated. The website Ratemyfishtank.com says: "You need to test your tap water for pH, gH, kH, and nitrates to understand exactly what is coming out of your tap. If the preferences of your fish are drastically different than your tap water's parameters, you may need to use a different water source."
  
  

Unknown Bottled Water

• The First Tank Guide website advises against using bottled water unless you know your tap water is unsafe. "Bottled water is often not regulated or tested, so the water parameters are unknown," it says in answer to a question about what type of water to use for fish tanks.
  
  

Bottom Line

• An angelfish can survive in tap water.scalare image by Henryk Olszewski from Fotolia.com
  
  Tap water is an acceptable choice for a fish tank as long as you know it to be free of anything harmful to fish. The First Tank Guide site says: "The easiest and most obvious--and usually the cheapest--is to use tap water. Tap water is available to almost anyone keeping an aquarium, and is almost always going to be fine for your fish."