Guppy

1 Species Overview

The guppy is distributed in the river basins of Venezuela, Guyana and the West Indies, among other places. Its other name is the millions fish, and its Latin name is Poecilia reticulata (guppy).

Phylum: Chordata

Order: Cyprinodontiformes

Genus: Poecilia

pH: 7.5–8.5

Kingdom: Animalia

Class: Actinopterygii

Family: Poeciliidae

Species: Poecilia reticulata

Water temperature: 22–24 °C

Food: tubifex worms, daphnia and prepared foods

2 Appearance

True to its name, the guppy has a tail like a peacock’s display, and its unique shape and easy care make it a hobbyist favorite. The guppy was actually introduced to Taiwan, China early on from abroad to help prevent dengue fever by controlling mosquitoes. There are now hundreds of guppy strains, which contest rules roughly divide into eight groups.

1. Grass: the tail has fine spots with no connection between them.

2. Mosaic: the tail has coarse spots that connect to each other.

3. Tuxedo: a clearly color-separated ‘tuxedo’ waist between the body and head.

4. Solid: the whole fish is a single color.

5. King Cobra (snake pattern): the fish has snake- or leopard-like markings.

6. Sword: the tail shows a single, double or bottom sword.

7. Albino: red or wine-red eyes.

8. Special tail type: fish with unusual fin and tail shapes.

3 Care Basics

Although the guppy is easy to keep, raising it well still takes care. First your guppies must be healthy; then mind these basic daily points to raise healthy fish.

1. Daily care

a. Suitable temperature and water: the guppy’s suitable temperature is 22–24 °C; water hardness 10–30 °dGH; pH 7.0–8.5. In poor water or when ill, its blue coloration can turn black.

b. Suitable food: good guppy foods are bloodworms, daphnia, or dry feed.

c. Tank size: use an aquarium of at least 45 cm for guppies (a mid-sized ornamental fish); the exact size depends on how many you keep.

d. Can be mixed: guppies are gentle and can be mixed with other gentle small/mid-sized tropical fish.

2. Care at the spring–summer transition

a. Keep temperature stable: don’t remove the heater yet; set a safe temperature such as 25 °C—above that it won’t run and won’t cost power. Also watch the temperature difference when changing water; new water that is too cold or too hot is unsuitable.

b. Lower density: to reduce waste and keep the water cleaner. (Needless to say, keep the filter running.)

c. Wash live food: especially for bloodworms—keep them 3–5 days with dripping water and aeration. From June to September when it’s hotter, avoid live bloodworms and feed frozen ones.

d. Disinfect tools: whether the fish are sick or not, any net, siphon, tank sponge, or even your hands that touched one tank’s water should be soaked in potassium permanganate or washed with soap before touching another tank. Owners with many tanks must heed this—fin clamping and ich spread fast and are a headache.

4 Tank Environment

Water quality is key when keeping guppies—get the water right first and the fish grow healthy. If you want to breed, the environment must be tuned to its best state. Here is how to raise healthy guppies, by temperature and stocking density.

1. Temperature: the guppy’s comfort range is 22–26 °C; I keep adults at 22–24 °C and fry at about 24–26 °C. Some hobbyists raise fry to 27–28 °C, believing it makes them active, increases appetite and metabolism, and speeds growth—true, but the downside of that high temperature is overlooked. At such heat, fry metabolism runs too fast; even eating a lot, intake can’t keep up with metabolism, especially calcium, so after a while sudden deformities and the like may appear.

Guppies kept as breeding stock are mostly fish spawned in winter, mainly because winter water temperature is steady and suitable.

2. Stocking density: for fry, in a 40×25×30 cm tank the suggested density is about 50–60 fish. Too dense and the water is hard to control and disease sets in—watch out! Too sparse, with a big tank and few fish, the fry won’t compete for food, losing activity and exercise, which slows growth—a point many keepers miss.

Generally after 2 weeks, as the fry grow, the tank’s density rises; if you don’t add space then, growth slows. I then move them to a 50×40×30 cm tank for room to develop faster.

5 Feeding

Guppies’ five common foods are prepared feed, live food, brine shrimp, daphnia and tubifex; what to feed varies with the fish’s growth stage. Like other animals, avoid a single food so the guppy stays balanced.

Feeding covers the type of food, the amount, and how many times a day, plus adjusting variety and quantity as the fish ages.

Newborn fry are not fed on day one—first to let them adjust, and because the yolk sac is not yet absorbed (guppies are livebearers). From day two, best is live brine-shrimp nauplii as first food: nutritious, easy to absorb, and it aids defecation. At this stage let fry eat their fill until the belly is half-round, leaving a little live food in the tank.

1. Prepared feed: many prepared feeds are sold, roughly three kinds—flakes, pellets, and frozen. These are the easiest to get and feed. Feeds made specifically for guppies are what most keepers use as staple, and they are nutritionally complete.

2. Live food: live food is always a mixed blessing—its nutrition far exceeds processed feed, but safety issues come with it, so keepers must be careful; otherwise the fallout may make you wish you’d only fed prepared food.

3. Brine shrimp: the safest live food is probably brine shrimp (nauplii). Preparation is quick and simple, but feed them soon after hatching—nauplii are most nutritious right when hatched, still with the yolk sac; if left too long the yolk is absorbed and nutrition drops a bit. If you hatch extra, freeze them and just thaw next time.

4. Daphnia: daphnia can be bred in green water, but don’t feed wild-collected daphnia directly—daphnia are intermediate hosts of Camallanus worms, and once infested, it’s no small matter to fix.

5. Tubifex: tubifex is very nutritious and survives long in the tank, letting guppies graze continuously, so they grow fast; it can also be a medicated carrier—feed the worm medicine first, then the guppy, which works well. It seems the perfect food, but because tubifex is wild-collected (some shops sterilize it first), no one can guarantee it carries no parasite eggs, so users must be careful.