The best gift here is probably a 10 gallon aquarium kit.  These usually come with everything required (though they often lack a heater) and are much better value for money than buying everything new separately.  Ten gallons is large enough to have a decent choice of species, yet small enough to keep costs down and be easy to find space for.   Five gallon kits are cheaper but they are much more restricted in terms of what you can keep in them.  If you have the money, 20 gallon kits allow a wider choice of species and decor, as well as increased stability in tank conditions which may make fishkeeping a little easier.

If you are short of money, check the web for second hand equipment.  Be careful to look over what you are buying carefully.  Remember that because it’s second hand, some of it may well be mismatched, missing or not work.  You may well end up buying the problem items new and this can raise the costs above what you initially estimated.  Been there, done that.  Even so, it can still be a lot cheaper than buying new.

Many people buy plastic kits that are cheaper than glass.  These are not such a good idea for a couple of reasons.  Most of these kits lack lighting, they scratch more easily and so don’t last as well, they don’t come with heaters, many heaters aren’t safe for use in them, and they may also lack a filter.  Many of them are also too small for anything other than a Betta or some shrimp.  If your budget is limited, I recommend second hand glass aquaria over these.

Another excellent gift is a book on aquarium keeping.  There’s a lot to aquarium keeping and having a decent book constantly on hand is a good way to prevent mishaps and respond to emergencies.

If the person you are buying for isn’t yet ready for fish, or isn’t sure that an aquarium is right for them, a book can give them a good idea of whether it is what they really want, and what type of aquarium would be best for them.

Don’ts when buying for new fishkeepers:

-Don’t buy the fish at the same time as the tank.  Get them after the aquarium has been set up for two weeks with plants in it, or fully cycled by another method.

-Don’t buy a goldfish bowl for a goldfish.  Goldfish bowls are far too small for a large, waste-producing fish like a goldfish.

-Don’t buy live animals immediately before Christmas.  The stores will be insanely busy and the salespeople won’t have time to help you as much as they normally would.  In bad cases, the animals may also not be as well looked after because the staff get overwhelmed.  Buy the tank, then go back and buy fish once the tank is set up and cycled.

-Don’t buy any pet you aren’t sure they want.

Here are some suggestions for groups of fishes that are compatible inhabitants for 5 gallon tanks.  I have only included fish is that are at least relatively easy to keep.

Note: I am assuming a standard 5 gallon long tank. If your 5 gallon tank is tall and narrow, it will support fewer fish as it is surface area that determines the number of fish you can have. There are a variety of rules of thumb people use for determining number of fish. For a properly-filtered tank of standard proportions containing tropical species, a 5 gallon tank should contain no more than 10 inches of fish. I have kept the fish inches here to 8.5 or less because this leaves more room for equipment malfunction such as short power outages and human error.

Cold water fish need more space – no more than one inch of fish per gallon in a standard-sized tank.

The tanks:
5 gallon tank with plants and a pH of between 6 to 7.

Fish Tank One: Amazon Nano Aquarium 1
6 Neon Tetras
1 Otocinclus

Fish Tank Two: Amazon Nano Aquarium 2
6 Black Phantom Tetras

Fish Tank Three: Betta Bachelor Pad
1 male Betta

Fish Tank Four: Lady Betta and Frogs
1 female betta
2 dwarf frogs
1 Otocinclus

5 gallon tank with a pH of 6.5 to 7.5

Fish Tank Five: Subtropical Stream
4-5 White Cloud Mountain Minnows

Fish Tank Six: Mini Catfish Tank
6 Pygmy Corydoras
1 Otocinlus

5 gallon tank with plants and a pH of 7.0  to 7.6

Fish Tank Seven: Where’s the Fish?
8 shrimp of any mix of species that doesn’t exceed one inch, Cherry shrimp is a good beginner species
1 horned nerite snail

Fish Tank Eight: Guppies, Guppies, Guppies
5 Male Guppies
1 horned nerite snail

Shrimp tolerate a wide variety of temperatures but temperature tolerances vary between species. Most will tolerate normal tropical aquarium temperatures, but some require higher temperatures and others are quite happy at temperatures lower than most tropical fish will stand.

Because shrimp keeping is a young part of the aquarium hobby, estimates of what temperatures a specific species like vary between sources. For example, the Amano shrimp is a common, well known shrimp in the hobby. Planet Inverts gives a temperature range for this species of 68-82F, while shrimpfanatics gives a range of 10-28C (50-82F) and most books on the aquarium hobby have no detailed information on aquarium shrimp at all! It is also noticeable that different captive-bred color varieties of the same species are sometimes given as having different temperature ranges. This is possible if the color varieties came from different areas or were kept under different captive conditions for long periods of time, but it is not very likely. It makes me suspicious of the information’s accuracy.

What can one do in such a situation? Pick what seems the most likely estimate for the shrimp you wish to keep. This is usually the parts of the range that overlap between sources. In the case of the Amano shrimp, that would be 68-82F. Watch your shrimp. Are they dying? Are they eating enthusiastically? Are they breeding? Adjust temperatures until your shrimp show the full range of healthy behaviors. Once you have this information, put your results up on the net and let other people know. In an area of the hobby this new, we all have the ability to add to what is known.

For those of you trying to pick a shrimp species, here are temperature ranges for shrimp with non-standard temperature tolerances. All information here is from Planet Inverts.

Aquarium shrimp that tolerate cool water (minimum less than 70F):

Amano Shrimp Caridina multidentata 68-82F
Bee Shrimp Caridina cantonensis “Bee” 64-78F
Caridina cantonensis “blue tiger” 69-81F
Caridina cantonensis “crystal red” 64-78F
Dark Green Shrimp Caridina sp. “Dark Green” 68-82F
Glass/Grass Shrimp Palaemonetes paludosus 64-85F
Golden Bee Shrimp Caridina cantonensis “Golden Bee” 64-78F
Neocaridina heteropoda 64-82F
Orange Bee Shrimp Caridina cantonensis “Orange Bee” 69-81F
Red Cherry Shrimp Neocaridina heteropoda “red” 64-82F
Red Tiger Shrimp Caridina cantonensis “Red Tiger” 59-81F
Snowball Shrimp Neocaridina cf. Zhanjiajiensis var. “white” 69-82F
Tiger Shrimp Caridina cantonensis 59-81F
Caridina cantonensis “white bee” 64-78F

Shrimp that require high temperatures (minimum 75F and up)

Brown Camo Shrimp Caridina sp. “Brown Camo” 78-85F
Cardinal Shrimp Caridina sp. “Cardinal” 78-85F
Harlequin Shrimp Caridina cf. spongicola “Harlequin” 78-85F
Orange Delight Shrimp Caridina sp. “Orange delight” 78-85F
Red Goldflake Shrimp Caridina sp. “Goldflake” 78-85F
Sulawesi Shrimp Sp. name not given, new intro. 80-82F

Sources:

Planet Inverts

Shrimpfanatics