An aquarium that is designed to go in the corner of a room is obviously triangular shaped. They come in different sizes, but the sizes do not normally extend upwards to the very large dimensions that a ‘normal’ aquarium can attain.
There isn’t any reason why a captive reef cannot be housed in a [tag-tec]corner aquarium[/tag-tec]. The reef is built outwards from the back corner and expands in width as it comes forward until it is at the position the aquarist desires. It is correct to say that the reef is not going to be as large as some are, but size isn’t everything. Consider some of the marvellous nano marine systems and how interesting they can be.
Lighting considerations are the same as with any shaped aquarium, as are filtration questions. If a sump is to go in a different location, a ‘standard buy’ aquarium can be used. Otherwise, what the aquarist can do if a sump is required (and it is desirable to have one) is to place it in the area below the display aquarium. It is likely that this will be a custom build to the aquarist’s exact requirements, again in the shape of a triangle. Water flow to and from the sump are the same as with any system. One difference is that, because of the shape, the return pump is often placed in the rear corner of the sump with a divider in front of it, leaving the rest of the area free for a sand bed etc. Access to the return pump is not usually a problem but needs to be considered.
The word ‘fish’ in the title could throw a different light on the subject. Unless the word ‘fish’ was simply a general word used to describe aquariums, it could mean that there is a desire to change a corner fish only tank into a [tag-ice]reef tank[/tag-ice]. This is exactly the same as conversion with a normal aquarium shape. Attention needs to be given to filtration (is it adequate), is the reef to be built of live rock or additional live rock (enhancing [tag-self]aquarium filtration[/tag-self]), is the protein skimmer efficient or does it need an upgrade, is water movement adequate or are extra powerheads required, and is lighting adequate for the livestock to be kept. Finally, account needs to be taken of the number and type of fish. A fish only system can house more fish per gallon than a reef, and also the fish in a reef system must be reef friendly.