school project

Question
I have a 5 gallon tank which is not completely full with 2 guppies 2 goldfish and a medium size snail.  This was setup for a school project, and we are supposed to find the optimal living conditions for the fish and snails and then alter with the pH, oxygen, ammonia and carbon dioxide levels.  Could you please tell me the optimal pH,oxygen, ammonia and carbon dioxide levels for guppies and goldfish.  Also, to test for all of those levels, do I have to buy test kits for each one? and how do you test for oxygen levels? Thanks!

Answer
Hey Tara,

I know you didn't ask this question to me, and sorry for the lengthy wait for an answer.

I cant tell you the optimum pH, ammonia, or oxygen levels! That's the basis of the project! However, i can help teach you a few things your teacher probably didnt mention so you can show them just how bright you are.

First, gold fish and guppies cant mix. They require such drastic differences in water quality, that there is no healthy combination to satisfy both fish for a long, healthy, happy life. Gold Fish require a largely acidic water (lower pH) and are cold water fish (they survive as low as 35*f!). Guppies are a tropical fish found in more basic water conditions (mildly high pH) and also like their water to be a bit harder then goldfish. What this means is the huge difference in water quality means the two will never be found in one area. For ammonia, I'll give you another hint too. As a fish breeder, I breed expensive guppies. If i can, i avoid all ammonia possible. If a water test shows 0 parts per million of ammonia, I'm thrilled. Nitrite and nitrate are products of ammonia being broken down, and if i can get a reading of less then 2 PPM of those, i'm extatic as well.

For oxygen and carbon dioxides, there really is no reliable test. The best method is to watch the breathing rates of the fish. In over crowded areas, fish will breathe faster, and their gills will flare out widely. This is similar to how we breathe after a 100 yard dash. To cure this, we use aquatic plants like bamboo, java ferns, horn wort, amazon swords, and a wide range of other things. If your teacher expects a scientific test, FreshLabs makes a CO2 test, but i find it far less accurate then simply watching the fish. With all life, there is a balance of how much CO2 can be present before suffocation begins. With fish, it's far different from guppy to goldfish to cichlid to shark. So, the best test to watch how fast the fish breathes.

On a side note, gold fish can grow over a foot long! After your project, it might be nice to donate your gold fish to a nice big pond where they'll be able to grow up and live a long, happy life. Guppies, however, rarely get larger then an inch and a half, so you could grab a couple more and stick them all together in your little 5 gallon tank!


As an fish care specialist, I'll have tips for care after the project if you're interested. Like, for example, you need to keep more females then males in your tank with guppies. The males will fight over who gets to breed with the females, and if the ratio is wrong, this can result in premature deaths.

Hope you ace your project! Good luck.