Frag Tanks

How Deep Should A Frag Tank Be ?

One of the key differences between a frag tank and a traditional saltwater aquarium is the depth.  While most tanks are at least as deep as they are wide front to back, frag tanks tend to be much shallower.  While the actual depth will be related to the other dimensions, most hobbyist frag tanks tend to be roughly 7”-8” deep.  Both our 6 and 12 gallon tanks are designed with a depth of 7”, perfect for a home frag tank.

So why are frag tanks generally shallower than traditional tanks?  Some of the reasons include cost of setup and maintenance, lighting and ease of access.  Since frag tanks are designed to serve a function rather than mimic a natural coral reef, they do not require the same depth for aquascaping.  A smaller water volume means a lower setup cost as well as less money spent on maintenance and additives.  Frag tanks also tend to not have a sandbed or rockwork so all the corals are placed on racks on the bottom of the tank, again reducing the need for a deep tank.

Since the primary purpose of frag tanks is to grow and store coral frags, light coverage and penetration is a key consideration.  Our tanks are designed to pair perfectly with the Reef Casa Halo light, although we also offer options that are both less and more expensive.  The Halo light offers the perfect balance between cost and output, as well as being programmable.  Since frag tanks are shallow, an expensive light is not usually necessary to achieve the needed PAR levels to maintain coral health.


Unlike traditional display tanks, where the general rule is “keep your hands out of the tank whenever possible” hobbyists generally find themselves putting their hands in a frag tank much more often.  Whether it is moving corals around on the racks, removing corals for sale or trade or moving the tank to a coral show, a frag tank is much more likely to be “hands on.”  Because they are shallower, reefers can move things around in a frag tank while only getting their hands and forearms wet, rather than their entire arms!  This also reduces the likelihood of chemicals from the skin being introduced into the tank.  While any tank can technically be used as a frag tank, Reef Casa’s shallow models make an ideal choice for saltwater hobbyists.