Which size tank?

[Markpd]

Which Size Tank?

Well you've got so far as deciding on a tank for your gerbils, but which size?! Making sure that your gerbils* have enough space is really important. The tank is your gerbil's house, they'll eat, sleep, dig, chew and play in there and you have to have enough room.

*Generally gerbils should not be kept alone, exceptions are gerbils too elderly for re-pairing, or more rarely a gerbil that's been proven not to get on with other gerbils. At the other end of the scale, especially for inexperienced owners you're better off sticking to just a pair, as larger groups are more likely to declan. In the wild a pair is the natural size of the stable part of the clan (mother and father), with pups leaving when/if grown up through the summer, or they may over-winter until spring if they are of a later litter. Assuming you don't want to start breeding gerbils (if you do, read this), a pair of brothers is the next most stable pair, followed by a pair of sisters.

I'm trying to gather more info here on the relative stabilities of different size and type of clans.

The Rough Guide To Tank Sizes

(please bear in mind, that when we say 'rule' we mean 'rule of thumb'. These are just guidelines)

The minimum rule to go by is, 20 gallons for a pair, then another 20 gallons for each extra gerbil. Clans of greater than four are not advised, except perhaps for very experienced owners.

One-Two gerbils = 20 gallon tank
Three gerbils = 40 gallon tank
Four gerbils = 60 gallon tank

The above rule means gerbils have adequate space to enjoy and exercise in. Your gerbils will still be healthy, but if you've got the means, space and want the best for your pet, then you should try and aim for more . You may be worried about the cost of larger tanks, but you can pick them up much cheaper if you buy them second hand.

A more optimal size for a pair of gerbils would be at least a 40 gallon tank (or larger), plus 20 gallons for each additional gerbil.

Tank size to volume converters here.

A Few Tank Setup Tips

If you do have a tank at the smaller end of the scale, then it's important that you shouldn't divide the tank up, for e.g a wheel or sandbath, but instead add a topper or a raised lid with a platform beneath it.

This is to allow the full width of the tank for digging, whilst making sure that the wheel and sandbath etc don't get buried. Whilst it is critical for smaller tanks, doing this for larger tanks too allows your gerbils a greater digging area. The topper/raised lid+platform don't need to be the full length of the tank, but it does need to be big enough to accommodate the various items of course. Examples of a divided tank, raised lid+platform shown below and a couple of toppers can be seen here and here, 2nd and 3rd photo for the latter.

A couple of notes, one about plywood, it should not be used on floors without edge protection. The other being about wooden stick barriers, when used vertically like that the gaps at the top should be filled in so that the gerbils can't get their limbs trapped there (I didn't know about that risk at the time!), see a little more about that in our general gerbil cage items guide.

Something that should be borne in mind with toppers and cages in general, is to be careful not to create a space where 1 gerbil can block off another gerbil. e.g if a topper only has one narrow entrance to it. Such easily defended areas can lead to territorial-ism and onto de-clanning. So either have a wide single entrance (which can't be blocked off by 1 gerbil), or have 2 entrances. [update 6/2023] Even then, a couple of owners have reported that it can still cause territorial issues, see here and here. In which case you need to switch to a raised lid design.

A divided tank to prevent the wheel and sandbath being buried!

Note, the water bottle was moved before the gerbils moved in.

I curved the barrier slightly to allow it to stand up (if you use a stick barrier like this, be careful to fill in the gaps at the top, see this thread for a little more about that).

Raised lid and platform allowing fully digging length in the cage (that was Blake posing there btw , more bedding was added later).

Gerbilariums

While some of these are a decent size, a common problem with these is that they don't allow deep enough bedding (we recommend a minimum of about 8"/20cm bedding depth, ideally 12"/30cm), sometimes this can be overcome by blocking off side vents or doors, and then accessing from the top, and providing more ventilation in the lid (or making a new lid).

The 10 Gallon Tank Issue

Is a 10 gallon tank suitable housing for a gerbil? Well the short answer is no, it isn't. Gerbils can't build proper burrows in 10 gallon tanks and they're a lot happier in a larger tank. The 10 gallon tank: fine for a hospital tank, as a split tank, clean-out tank, split-tank (for intros) or temporary accommodation, and that is it.

Typical sizes of a '10 gallon' tank are :-

 

18"x12"x12" (~46 x 30 x 30cm)
20"x10"x12" (~51 x 25 x 30cm) (US)
= 9.3 Imp. gallons
= 11.2 US gallons

= 42.4 lts

Minimum tank size guide

Here are the dimensions of the tank (in inches, feet and cm), the volumes in gallons (both UK and US) and litres, and the maximum no. of gerbils you should have in each size of tank.

Actual tank capacities are rather confusing, it seems their labelled capacities refer to the amount of water you would realistically put in them as an aquarium (you wouldn't brim them). Of course we're not, we're interested in the whole volume, hence the different figures!

2 gerbils

'20' gallon tank

24"x18"x12" (2 ft x 1.5 ft x 1 ft) (~60 x 45 x 30cm)

= 18.7 Imp. gallons

= 22.4 US gallons

= 85 lts

3 gerbils

'40' gallon breeder tank

36"x18"x16" (3ft x 1.5 ft x 1.25 ft) (~90 x 45 x 40 cm)
= 37.4 Imp. gallons
= 44.9 US gallons
= 170 lts

4 gerbils

'60' gallon tank

48" x 13" x 23" (~122 x 33 x 58 cm)

= 51.7 Imp. gallons

= 62 US gallons

= 235 lts

Some 'Good' size tanks :-

2-4 gerbils

250 ltr tank/3.25 ft tank

100 x 50 x 50 cm (~39" x 20" x 20")

= 55 Imp. gallons

= 66 US gallons

300 ltr tank/4 ft tank (not cheap new, currently £229 as of 12/2021)

120 x 50 x 50 cm (47" x 20" x 20")

= 66 Imp. gallons

= 79 US gallons

450 ltr tank/5ft tank (when new, these are really expensive! Currently £345)

150 x 50 x 60 cm (59" x 20" x 24")

= 99 Imp. gallons

= 119 US gallons

540(!) ltr long/6ft tank (when new these are ludicrously expensive! Currently £683! )

183 x 50 x 60 cm (72" x 20" x 24")

= 119 Imp. gallons

= 143 US gallons

Some random info for various tank/cage sizes + volume and floor area

75x45x38 cm, '30' gallon tank ....................................................... (128 lts, 28 imp gall, 34 US gall, 3375 cm2, 523 sq inches)

Germany - Min. recommended. 100x50x50cm (2-6 Gerbils) ........... (250 lts, 55 imp gall, 66 US gall, 5000 cm2)

Swiss - Min. required 100x50x30 (2-5 Gerbils) .............................. (150 lts, 33 imp gall, 40 US gall, 5000 cm2)
Swiss - recommended 120x60x60 ................................................. (432 lts, 95 imp gall, 114 US gall, 7200 cm2)

120x50x50 cm aquarium ............................................................... (300 lts, 66 imp. gall, 79 US gall, 6000 cm2, 930 sq inches)
150x60x60 cm aquarium ............................................................... (540 lts, 119 imp. gall, 143 US gall, 9000 cm2)
Ikea detolf 163x43x37 cm ext, int. 158x38x36(?) cm .................... (216 lts, 47.5 imp gall, 57 US gall, 6004 cm2)

What happened to the max size 'rule'?

This rule was in place because it was thought that bigger tanks could supposedly cause de-clanning between gerbils (hostilities which can lead to lethal fighting), however it would appear that idea was misplacing the cause of declanning. Many owners, breeders, rescue ctrs, and researchers in the UK, US, and Europe believe that large cages causing declanns is a myth. I did some research on it myself here.

Article contributors:-

Myself! (see above link) And thanks to the following for their help

betty

LilyandDaisy

PipSqueak

ashgerbil, from her original Which Size Tank guide from 2007 for the FAQ, which this article is partially based on.

__________________________________________
Thanks To...

Danielle (Shootingstar) for some of the US tank sizes

Any comments or discussion of this guide can be carried out in this thread.