Tips for Tidying Up You don't need to be the Marie Kondo of aquarium owners to maintain cleanliness. Implementing a few simple tips streamlines the routine. Start Up Right, Save Stress Later Investing in the appropriate sized tank and filter is a must. Make sure you do your research beforehand. A good rule of thumb is that a 10-gallon tank can house roughly 3-5 fish of less than 3 inches in length. From there, you'll want to go up by increments of ten when it comes to building an aquatic paradise. Don't skimp on the filter! A sturdy filter can save on daily maintenance and keep your fish thriving between cleaning. Fishy Foodie helper to your tank! Snails and plecostomus are great at cleaning up the grime.