Snail appeared suddenly in aquarium, is that normal?

Yes its normal. There are many articles written for it, How to Deal With Aquarium Snails Perhaps you have had the experience of looking over your tank one day to find an unexpected guest cruising along your tank wall. read more

Some of the best snails to keep in your aquarium include: Apple Snail – the apple snail is one of the most common species of snail kept in the freshwater aquarium. These snails come in all colors, but the most common color is blue. Apple snails can grow to be fairly large, up to 6 inches (15cm) in diameter. read more

Buck McDaniel, I've owned and maintained Aquariums for over 40 years. read more

Snails or snail eggs can arrive on/in any object that has been in another aquarium. Look upon them as your true friend in your fish tank. Snails perform tasks you never could, getting into tight spots to eat organics and break it down for the bacteria to more easily handle. read more