Which to Choose - a Small or Large Aquarium

Most aquarists are dictated to by circumstance. There is a really big aquarium, at a really good price, but one rather definite problem, and that is there’s nowhere to put it. So a smaller aquarium is chosen, but not by choice. However, even in the described circumstances, a smaller aquarium could be the one of choice.

Most aquarists dream big, visualizing that final aquarium that will bring the ultimate reef. In most cases, it never materializes. Some are lucky of course. There are some beautiful big reefs about.

There are also some beautiful small reefs about, but the beauty is not ‘in the face’. It is in the detail.

There is one aquarium type where, I would imagine, bigger is usually best. That is the fish only aquarium. When an aquarium system is considered, between reef and fish only, if say angels and butterfly fish are to be kept, then fish only is the choice. Some angel and butterfly fish are said to be reef friendly, but many are not. The aquarist with a big fish only aquarium will have a lot of choice of fish, with all the colour and interest that goes with them. If the aquarium was smaller, then fish loading would have to be reduced. This does not mean to say that a fish only small aquarium is a waste of time, it is not. In this case, though, the choice of fish is limited, in size and territoriality. For example, it would be wrong to house a surgeon fish in a nano aquarium.

Small aquariums such as the nano should house fish of appropriate size. Perhaps the common clownfish (Amphiprion oscellaris) would be suitable, or other small fish such as the Neon goby (Elacatinus oceanops) and similar. In the larger nano aquarium, fish such as dwarf angels (Centropyge sp) could be suitable. Stocking levels have to be a disciplined affair with the very small nano aquariums, and not excessive with the larger ones. The fish only aquarium of whatever size has the advantage that, although water quality is important, there is no great need to worry about calcium and the like, the need being to keep nitrates and phosphates as low as possible. So if the desire is to have a good number of exotic fish which may not be reef friendly, a larger aquarium will do. If the idea is to have one or two small fish then a nano will be fine. Both types will need suitable decoration for the fish to feel secure.

If the aquarist yearns for a reef tank, and wants to emulate as close as possible the corals of the reef in quantity then a larger aquarium is going to be required. The fish stocks have to be controlled as reef unfriendly fish are not required, and too many fish will tend to depress the water quality despite modern equipment. The aquascaping of the reef is fun, and the aquarist will, with care and attention, achieve a beautiful reef. The reef will never properly emulate nature’s own, of course. There is a lack of size, a lack of diversity, and reef unfriendly fish are missing.

Then there is the aquarist who is very interested in detail. They do not want a big reef, but a very small section of a reef so the detail of the development of the life on a rock or two can be watched in particular. Or perhaps the antics of two small fish are the attraction. Here the nano will be suitable, as a ’live’ rock or two of suitable size will be all that is required. Then the aquarist can stock a coral or two, plus perhaps a suitable shrimp, or go for a fish or two. It is most probable that the aquarists who deliberately choose a nano tank when there is room for something larger are few.

Again as said, most aquarist’s vision is of the big one. The nano aquarium also brings the fascinating marine world more within the reach of the aquarist with a restricted financial ability.

There are aquarists who run a larger reef aquarium and also run a fish only one as well. This is probably the best of both worlds. Then there are the aquarists, usually advanced, who run a larger aquarium of whatever type and also run a nano aquarium, sometimes two, so that particular aspects of marine life can be studied.

So what are the advantages of a nano aquarium? The term nano is applied to an aquarium up to 50 gallons. The nano can start at a size of 10 gallons or slightly less. So it becomes pretty obvious that the set up costs are minimized. In the fish only nano, there is the cost of the fish, of course, and the seawater mix, and any sand base that might be used, and the heating/lighting. Plus any ordinary rock which is required. If ‘live’ rock and one or two small corals are incorporated then the cost will rise but not significantly. So the demand on the wallet is not going to be high. Running costs are low. Water changes will not amount to many gallons and are effective, if done weekly, to maintain water quality. If there is a calcium etc requirement then commercial additives should last a long time. There should be no requirement for expensive add-on equipment. If desired nano aquariums can be purchased ready for use at reasonable prices in designs that fit into the modern house well. There are potential problems though. If the aquarist overstocks then water quality is going to suffer. The small seawater gallonage is subject to negative change, maybe caused by the aquarist (overfeeding, overdosing), or caused by external influences (overheating). So the nano aquarist has to be extra vigilant on water parameters.

What of aquariums that are over 50 gallons in capacity? The bigger they get, the more money is going to be needed. The cost of a fairly large aquarium, when furnished with ’live’ rock, sand bed, protein skimmer, corals and fish can run into thousands. Not cheap. Likewise the fish only system. The large amount of seawater required, any ’live’ rock used, a protein skimmer, sand bed etc plus all the fish again is a significant cost. Larger aquariums can also be purchased ready for use. The cost of these is very high. Against that, the larger aquariums are more naturally stable. The aquarist needs to make a major blunder to badly overdose the aquarium. Feeding likewise, though the larger numbers of fish in a fish only aquarium plus overfeeding could spell trouble. External influences can cause problems with overheating, the larger aquarium does not escape this. Halide lighting and warmer weather will cause a temperature rise. However, the temperature rise will occur more slowly because of the higher volume of water. Generally, as the aquarium is larger it is usually easier, more practical, and financially more acceptable to take action to control temperature rise with fans or, if really necessary, a cooler (chiller). By this it is meant that fixing cooling apparatus to a larger aquarium is easier than doing so with a very small nano aquarium, and the high cost of a seawater cooler is more acceptable on a very expensive aquarium. It can be done with a nano, of course, and for the sake of the life in the aquarium stable parameters are needed.

So, it’s ‘horses for courses’ as they say. We each have our own ideas and we know our financial capabilities. Whatever the choice, marine life is fascinating.