Where do the fish come from?

Question

If you have a pond or a large pool of water, and it is cut off from other sources, where can the fish in it come from?

For example, there may be a volcano crater that erupted a long time ago and is now dominant, After a long while, its surface will cool and rain water will collect in the crater. Over time, fish and aquatic life will be formed in it.

Where did this aquatic life come from? Can't the pond or water filled crater be devoid of all life?

Answer 1

Hurricanes and tornadoes can pick up fish plants and animals and transport them many miles where they rain down to earth.

Birds can pick up fish eggs and then drop them. Some fish eggs can pass through the body of a bird or other animal.

Answer 2

maybe they just....spawn

Answer 3

Often previous geological processes can create the scenarios you're describing. A volcanic crater may have underground connections to another body of water, such as old lava tubes reaching down to the sea, for example. In other cases, the lake or pond we see today is the remnant of a much larger body of water that may have had rivers, etc. Over time the conditions changed, so that all we have today is a much smaller version, complete with fish, which are descended from earlier species trapped when the rivers were cut off, or the pond was reduced in size, etc. Loch Ness in Scotland is a good example of a lake that was left over from the last ice age, but is now (apparently) cut off from the North Sea

Answer 4

Since there fish are in ponds or large pools of water that doesn't mean a hurricane or tsunami picked up the fish. People take the fish in a big water tank and then put them in the body water and feed them.

Also, the first fish that there was, was created by God and then fish were born out of those fish.