This page contains some advice on how to test your fish's water by looking at it and by smelling it. You don't need fancy test kits to find out a lot about your fish's water.

The glass on the left contains tap water straight from the faucet in my house. The glass in the middle has water that I scooped from the surface of my pond. The glass on the right has water that came from the bottom of my pond.

Click here to see my nephew, Nicholas, cleaning the gravel in the bottom of my small pond. You can see some of the green water from the bottom of my pond in his bucket. This is the same green water that is in the drinking glass on the right in the picture above. Removing this green water from my pond, and replacing it with fresh tap water from the faucet, helps keep the water in my pond clear and clean.

Can you see that the water in the middle glass in the picture is slightly tinted with color? This tint indicates that I need to change water more frequently in my pond.

So I'll use my Gravel Washer every day to remove 20% of the water from my pond, and replace that water with tap water from the faucet, until the water from the surface of my pond matches the the tap water that comes out of my faucet. Click here for about Gravel Washers.

Get two matching drinking glasses with clear glass. Put tap water in one drinking glass. Put some water from the surface of your aquarium, fish bowl, or pond in the other drinking glass.

If the water from your fish's home looks tinted or slightly colored, then you need to change 20% of the water every day, until the water water from your fish's home matches the tap water from your faucet. Click here for more about changing water.

Is Your Fish's Water Cloudy or Foamy?
Every day when you look at your fish, or feed them, or change some water, take a minute to look closely at the water too. Check to see if the water is cloudy, or foamy, or has an unusual odor. Look at the edges of the surface of the water near the glass.

Can you see a little bit of foam? Or maybe just a few bubbles? If you have a power filter, does it produce big bubbles that float on the surface of the water and don't pop quickly ? Do you have a decorative air stone or bubble-wand that creates a stream of bubbles and some of those bubbles don't pop quickly after reaching the surface?

If you said yes to any of these questions, your fish are living in water that is not good for them, and you should click here for a list of what to do. Or if the water is green, click here for a list of what to do.

In our facilities we rarely test the water with test kits or chemicals. We used to test for ammonia and nitrite and do other tests too. But most of us working here can spot poor water by looking at it. If in doubt we stir the water with our finger tips to see how quickly the bubbles pop.

If we see an aquarium with cloudy water or bubbles or foam on the water's surface, and the bubbles don't quickly pop, we take immediate action to clean the aquarium, the filter, and change some of the water. Click here for more about cleaning your fish's home.

But Cloudy or Foamy water often does not smell good. Rather it smells like garlic or cigar smoke. I've been smelling fishy water for many years, and the smell is often an important clue in helping to decide whether the water is good for fish or not good.

If in doubt, clean your fish's home and change 20% of the water each day, until the water quality looks and smells good again.