I get the same effect with the outflow of my small bottle filters. Though I power these bottle filters with small water pumps, air bubbles from air stones and air driven sponge filters provide another important function – they provide surface agitation, which promotes oxygen exchange. Even though my tanks are sufficiently filtered with canisters, I often keep small, DIY bottle filters running just to provide a little extra filtration and to provide some redundancy in the event a canister goes down.

You already have all the other components needed if you’re running an airstone (air pump, air line) and you’ll still get the bubble effect but you’ll be adding some biological filtration in the process. Sponge filters are readily available at your LFS or online and they come in all shapes and sizes. If you have air stones or bubble walls in your tank, you can add a little more filtration to your water simply by replacing your air stone with a sponge filter. Watch your cichlids closely when they eat and you might just see the pharyngeal jaw muscles at work. In fact, if you’ve ever kept clown loaches (Chromobotia macracanthus) and heard the clicking sound they make, you’re hearing the pharyngeal teeth grinding together. They’re also used to produce sounds for communication purposes. Interestingly enough, these teeth aren’t only used for processing food. This pharyngeal jaw action, often unnoticed to the naked eye, breaks down food for passage through the esophagus into the gut. In addition to whatever oral teeth they may have, all cichlids possess tiny teeth on the pharyngeal plate in the throat that are used to grind up food. One of the defining morphological characteristics of the family cichlidae is the existence of pharyngeal dentition. How intently do you watch your cichlids when they eat? If you pay close attention when they eat anything more substantive than flakes (e.g., pellets, discs), you’ve probably noticed the food completely disappear but see little movement in the oral jaws.

Red zebra cichlid bare bottom