Loaches spend most of their time on the bottom (whether in the wild or in your tank), exploring their environment and looking for food. They come in a variety of colors and also have a wide range of behavior patterns, with some loaches being extremely peaceful and others more aggressive. The loaches most commonly found in the hobby today are naturally found in China, India, Thailand, and a few other places. Loaches are fairly easy to keep as long as they are provided with a smooth substrate (to avoid damage to their tender underbelly) and a few places to hide and rest during the day.
There are over two-thousand species of catfish, hundreds of which are available in the fishkeeping hobby. Some catfish make great community fishes, while others are better kept alone or in a planted tank. Most catfish will spend the daylight hours in hiding. Likely the only way you will be able to see your catfish on a daily basis is if you plan the feeding time in the evening, after the lights are out, when your catfish will feel most comfortable being exposed.
Plecos make up the largest group of catfish, which is the family Loricariidae. This family includes more than 450 species. Plecos are found naturally throughout most of South America and some of Central America. Additionally, they have managed to establish themselves in the waters of Florida, Hawaii, Australia, and several other locations with water parameters that are very similar to those that these fish naturally habitate. They can range in size from several inches to several feet, with some of the smaller varieties making great pets for first-time fishkeepers.