Reply. Hello Sherry. As you observe in your aquarium, ten male Guppies with seven females is not a good ratio. The best ratio is at least
three males and about twice as many females.
So three males and six females is good. You have a total of 17 Guppies, and if you had five males and twelve females, or even six males and eleven females, then it would be a
Incidentally, mammals like me, my cat, and the dog, that lives next door, all have X and Y chromosomes, which create about 1/2 males and 1/2 females in each species of mammals.
But Guppies and other livebearing fish have X, Y, and Z chromosomes that produce about 1/3 males and 2/3 female Guppies. So the normal ratio for Guppies is two females for each
male, and this may be the reason that this ratio works better in aquariums too.
You should be able to keep at least 25 Guppies in your 35-gallon aquarium. So you could get eight more females now to make a group with 10 males and 15 females, and that would
make a much better group of Guppies.
So you don't need to move any of the Guppies to your other aquarium, which contains fish, like the Swordtails and Red Tail Shark, that are definitely not compatible with the
Guppies. Click here to read about compatible tank mates for Guppies.
Your Neon Tetra should be in a group with at least six Neons, and Neon Tetras are not compatible with the Swordtails or with the Red Tail Shark. Click here
for more about Neon Tetras and other small Tetras.
Incidentally, Swordtails are livebearers like your Guppies, and all livebearers live best in a group with at least three males and twice as many females. So you may need more
Swordtails. Click here for more information about Swordtails.
Red Tail Sharks, like yours, live best with only one in an aquarium or in a group with several Red Tails Sharks. I usually recommend at least six, but I've received several
recent emails, that say it should be eight or more. So it's usually best to keep just one, like you have now. Click here for more
information about Red Tail Sharks.
Your White Clouds should also live in a group with six or more White Clouds, and they, like Neon Tetras, are compatible with Guppies but not with your Swordtails and your Red
Tail Shark. Click here for more about White Clouds.
If you follow my recommendation and get eight more female Guppies and also add your Neon, plus five more Neons, plus six White Clouds to your 35-gallon aquarium, then all these
new fish may produce too much more waste for your filter.
So you should add the eight females Guppies and move the one Neon to your 35-gallon aquarium, then in about three weeks get five more Neons, and move the White Clouds to your
35-gallon aquarium. Add White Clouds to make a group of at least six White Clouds.
You also asked about moving fish. It's best to freshen both aquariums before you move fish from one aquarium to another. To freshen an aquarium, do a partial water change by
removing 20% of the water and replacing it with freshwater. Do this each day for three days before you move the fish.
Also be sure the temperatures of the water is within a few degrees. I think it is actually better if the aquarium receiving the fish has slightly warmer water. For example the
fish may be in water at 77 degrees F., and they are moved to an aquarium with water at 79 degrees. So you might adjust your aquarium heaters during the three days that you are freshening the
I hope these comments help you and your fish.