Getting the temp the same.....

[Joanna]

When you do the water changes how do you get the new water the same temperture as the old stuff you had in your tank so you don't hurt your fish???:confused:

[Dangerdoll]

you could hold a thermometer under the water flow and keep adjusting the hot/cold until the temp matches that in the tank...

[OrionGirl]

For many fish, if you are changing around 20-25% of the water, the new water should be close, but it doesn't have to be exactly the same temp. I filter water into a tub, and it is usually around 65F when I do my changes. The tank is around 76-78F, and I have never had a problem. The overall temp of the tank only drops 2-3 degrees, which isn't a big deal for most fish to handle--heck, for some species, it initiates spawning!

For sensitive fish, you can use mix hot and cold waters if you fill straight from the tap. If you use filtered water, or allow your water to sit in a tub overnight to gas off chlorine, just use a small heater.

[JSchmidt]

For all but the most sensitive fish, a swing of 5-7 degrees won't cause a problem. If you consider that most water changes don't even approach 50%, one could imagine that the water used for a partial change could be pretty discrepant in temp from the tank temp without causing a problem.

Some fish (e.g., many africans) are actually encouraged to spawn by changes with cooler water.

Matching temps by touch is usually OK.

Jim