One of the common questions from novice breeders is, "Is this clump I have my fishes' eggs or snail eggs or something else?" Another common question is, "I have these fish and which one laid these eggs?" For livebearers and mouthbrooders, this question is not needed since the eggs are kept out of the aquarist's view inside the fish. For egg scatterers, eggs look like tiny clear balls that stick to whatever they landed on, including each other. For labyrinth fish, the eggs are very tiny, clear balls suspended in the bubble nest. With egg depositors, the eggs are usually larger and stuck on some surface. Cory catfish often stick their large eggs on glass and plants, and some species have colored eggs. Look into what the eggs look like for each species in the tank to determine which one laid the eggs. After a day, black spots should appear at the center of each egg that was fertilized. Later (a few days), you should be able to discern a pair of eyes looking at you if they are indee fish eggs.

The other possibility is snail eggs or even foreign matter like empty fish feces. For example, sick goldfish often release clear strands with no matter inside when they are ill. Snail and amphibian eggs are usually gelatinous masses. Snail eggs will usually be in clumps on surfaces either in or out of water (depends on species), and amphibian eggs will usually not be stuck to anything but each other or perhaps anchored to a plant. If you still cannot decide what laid the eggs or debris, put them in a small container or tank of water at the same temperature and pH as the main tank or pond and wait. Check daily to see if something is growing in the "eggs." If they are fish eggs, the eyes of the fry inside the egg should be obvious as hatching nears. If after two weeks, nothing has been born, then you will never know if they were good eggs that died, unfertilized eggs, or just some debris.