Question about Schooling (Danios) and pH problem?

Question

I put 2 Zebra Danios inside my new 10 gallon tank yesterday; and even though it may be a little bit early, I am planning to add more fish after the tank is cycled. I have done some research on Zebra Danios on the internet, and most people suggest to keep at least 6 of them in the tank because they are schooling fish. So, do I need to put 6 Zebra Danios for them to school? Or can I have 2 Pearl Danios, 2 Zebra Danios, 2 Leopard Danios (or other Danios) to school together?

Another question I have is about the pH value of the water in my tank. I brought a water sample to Petco to have them test the pH before I bought the fish, and they said the pH of my water is about 6.5. Then when I came back home, and test the water with the "Master test kit" I just bought, I found the pH to be around 7.4. Therefore, I am kind of confuse right now, and I am not sure what I should do. Does anyone have any suggestion?

(Note: I tested using test tube and pH solution, while Petco test ed using pH paper)

Answer 1

Zebra Danio and Leopard Danio school together very nicely and will do wonderfully together. The Pearl Danio will usually join that school as well, so I wouldn't worry at all about getting more of any of those fish, it's entirely up to you. If however you want to insure they can school comfortably, stick to a mix of Zebras and Leopards.

The pH readings you got are certainly not out of the realm of possibility and much of the answer would depend on the carbonate hardness, or alkalinity of your tank. If it's naturally a bit low, then the pH can change as much as the 2 tests indicate. That would not be a really common event, so I would suggest you test your tank again and also test your tap water. I bet you will find them to be rather close to each other and that's a good thing.

As far as what to do about the pH, do nothing. Either of those values are easily within the comfort range of most fish you will encounter in an aquarium store and further, your local fish will be acclimated to your local pH, so just leaving it alone is certainly the best answer. Remember this, a stable pH of most any number is far better than a pH that bounces around a lot from trying to adjust it. So do yourself and your fish a favor and don;t adjust your pH.

MM

Answer 2

Good job for doing your research, it is indeed recommended that zebra danios be kept in groups of six, but I have done, and seen it done where they are kept in groups of three and they seem to do just fine. I had three and they started spawning, so they couldn't have been too sad in a group under 6. Some different species of danios will school together, so you should be OK with a combo of different danios.

About your pH, there is always a slight difference between testing methods, it is difficult to get the same results out of different testing kits but the difference you described is a bit high. It is possible that the danios you added contributed to the pH or your tank is not done cycling which may cause a spike or drop in pH. I would test it again in a week or so then bring a sample to PetCo again just to be sure.

Answer 3

It is best that all danios be kept together in groups of 6. This includes Zebra, Turquoise, and Glo-fish. You can have only up to 12 fish in a 10-gallon aquarium so choose wisely.