Introduction to Favia & Favites
Favia and Favites are two genera of coral, which include a large number of coral species found commonly in the aquarium trade. They come in a wide variety of colors, patterns, and polyp size. Chances are you will find at least one coral from these genera in most hobbyists’ aquariums. In this article, I will begin by describing the general appearance and growth patterns of these corals as well as how to identify these two groups. Then, I will talk about coral placement and coral preferences as far as lighting, water chemistry, and water movement. Finally, I will discuss the feeding requirements for these corals. While genetically these are separate lineages and quite a diverse grouping of corals, when it comes to aquarium care they generally have the same requirements. This article is intended to give the reader a basic understanding of these corals and provide enough background to keep these corals healthy and happy.
Identification: Favia vs. Favites
Both Favia and Favites are referred to as Large Polyp Stony (LPS) corals which means they grow a calcium-based skeleton upon which individual polyps live as one communal animal. Each circular polyp is oriented around a central mouth (or multiple mouths, depending on the species). At night, or in response to feeding, tentacles may emerge from around the mouth which are used to catch and consume food from the water column. Most members of this group will grow both laterally and vertically. Over time they will begin growing and encrusting onto the rock they are resting on. If given enough time, they will eventually become completely attached to the rock they sit on and will sometimes even fuse separate rocks together. These genera will also mound higher by layering their skeletal structure on top of itself. Some species create dome-like structures that have the shape of a brain, which is why their common name is “Brain Coral.”
Telling these genera apart is often an exercise in confusion. To make matters worse, there are other genera such as Goniastrea which are frequently mistaken for and sold as Favia. I’ll admit, even I have a tough time on occasion! That said, the actual genetic relationship between corals is still an active area of research. Most coral have not had their genes sequenced, so scientists often rely on the relatively inaccurate method of looking at the shape, size, and frequency of corallite polyps and septa to determine relationships between coral. Many species were described long before DNA identification was even an option so expect changes to occur as scientists gain a better understanding of how corals relate to one another.
To give an example of how confusing species descriptions can be, the genus Favia is described as, “Plocoid, forming by mono-tristomodaeal budding, massive, foliaceous, or encrusting colonies. Basal epitheca present. Permanent condition of corallites monocentric. Columella parietal, spongy. Endotheca and exotheca vesicular.”
While Favites is considered to be, “Like Favia, but cerioid, walls usually septothecal”.
Absolutely crystal clear right? To put this description into super simplified layman’s terms, it is essentially saying that Favia form large colonies with roughly circular corallites (a.k.a. polyps). The polyps are separated from each other by a raised wall and there are ridges (called septa) both inside and outside the wall. Favites are “like Favia,” but the walls are usually formed by the thickening of the septa.
Ok, maybe that is still not super clear! In general, the easiest way to tell these two genera apart is to look at how the polyps connect. In the case of Favia, each polyp appears to be separated by a line or roll in the surface tissue. In contrast, Favites polyps appear to connect at a ridge because the corallites share a common wall formed from a thickening of their septa.
If you are interested in finding out what each scientific word in these descriptions means, here is a handy glossary that contains most of them: http://www.coralsoftheworld.org/page/glossary/
Favia & Favites Placement: Lighting and Water Movement
While both groups of coral are placed in separate genetic families, their care is similar. They are reasonably easy to maintain in captivity and are great corals for intermediate beginners. Provide them with low to medium flow and moderate light. When acclimating to a new tank, they are usually best started off at the bottom and can be moved higher over time as they adjust to the lights of your aquarium. If you purchase coral from us and have a PAR meter it is generally advisable to shoot for about 100 PAR when acclimating but most of our corals are kept closer to 200+ PAR in our grow-out tanks. In my experience, it seems that red color morphs are typically adapted to lower light and seem to be less tolerant to higher intensity lighting. The deep red Favites pictured above sits at around 150 PAR. Even without a PAR meter you can use the coral’s color to determine if it is getting enough light. If you notice the tissue coloration getting lighter, move the coral to a less bright location. Conversely, if coral tissue begins to darken and turn brown it needs more light. When placing this coral, be aware that they have moderately long tentacles and can unfold and sting neighbors, especially at night. They have also been known to send out long white strings called mesenterial filaments which can absolutely destroy any unlucky neighbors.
FAVIA & FAVITES Water Chemistry
As with most coral, stable levels of alkalinity and calcium is a must. Alkalinity from 7.6 to 8.6 is recommended for most people but some reef keepers push their levels higher. Stability is key in any case. Calcium should be kept from 400-450, the uppermost of that range being preferred. Low nitrate below 10 ppm is generally preferred. Trace elements should be added deliberately or via routine water changes.
Favia & Favites Feeding:
While many reef keepers do not specifically feed their corals Favia will extend feeding tentacles at night and love to be fed any small meaty foods. Mysis shrimp, finely diced table shrimp, scallop, or other tiny foods are all accepted. Smaller pieces are always preferable because they are easier to digest. There are also a wide variety of commonly available coral foods for those who want pre-made food. At Ridgeline Aquatics we find that our Favia love Coral Frenzy Reef Pellets and Polylab's Reef Roids but there many great options out there. (Both of those are affiliate links that give us a tiny kick-back at no cost to you if you choose to purchase from Marine Depot) While these corals will attempt to consume large quantities of any offered food, care should be taken not to overfeed! You do not want to reduce overall tank water quality nor do you want to feed more than the coral can actually digest. A light dusting once or twice a week is generally plenty. Coloration and growth rates are noticeably impacted by feeding a few times a week especially if the aquarium has very low levels of nitrate.
You should now have a basic understanding of the differences and similarities between the genus Favia and the genus Favites as well as considerations for tank placement, water chemistry, and general care requirements. If you have further questions or comments be sure to leave a message below.