To return to trout. These fish, when about a year old, are very interesting, and if a constant change of water can be secured may be kept alive for years. Even without this advantage, I have kept them many months, and have found their little ways very curious.
The trait I objected to the most was the habit of cannibalism which the larger fish developed. I found one fish of about one and a half ounces with another about half that size half way down its throat.
This makes it desirable to keep only such trout as are about the same size together. They will gradually, though very slowly, get tame, and will come out from their shelter under a weed to eat a caddis as you drop it from your hand. This was only the case with some of the fish, others remaining as shy as ever in spite of petting.
It is best to choose fish that have been taken by net, but trout taken by a fly, or roach taken by a small hook in the lip, will live very well.
I have kept trout for months that I had caught with fly and carried home for miles. Some of these were from a quarter to half-a-pound in weight; but I found smaller fish would thrive better.
For food, caddis or other water insects are best; but gentles would perhaps do, if the former are not to be had. I found the freshwater shrimp capital food, as it keeps alive, of course, till the trout is inclined to eat. One of the chief causes of mortality in the aquarium is the fouling of water by the decomposition of surplus food. If you are obliged to use dead matter, such as chopped liver, or meat, be careful to remove any that may be left.
Flies may be put on the surface, and will be appreciated; but the trout will seldom take them while you are watching, though they will often eat the caddis as you put them in, and even chase the shrimps.
On the whole, I think perch are the best fish to make pets of, as they can be taught even to take worms from your hand, and require much less water running in and out than do the trout. I’ve known a perch to live for years in a tin bath in my stable; whereas the trout would not be happy without a long tank, and continual change of water.
If you have only a very small aquarium it may be better to be contented with a few minnows. These, with the water weeds and little fresh-water snails, which should be in every aquarium, will be quite enough to make it look pretty.