Guppy care for beginners

This is first because it is the only item on this page that a care authority describes as required rather than advisable, and because guppies are routinely sold as an unheated desk-tank fish.

OATA's range is 20 to 28 C. A room that sits at the bottom of that during the day will fall below it overnight, and a small tank follows the room closely.

Fifty watts is the right wattage for the 10 gallon tank this page recommends as a floor.

The honest costs. It is preset, so you take the temperature the maker chose rather than dialing your own, which is the main argument for spending more on an adjustable unit if your room runs cold. No thermometer is included, so the setting is a claim rather than a reading. And a glass heater is easy to knock in a small tank.

Guppies are livebearers from hard water, and this is the single most useful number for predicting whether a colony thrives or slowly fails in your house.

Keepers in soft-water regions lose guppies steadily while every reading on the master test kit says the tank is perfect — because the master kit never measured the parameter that was wrong. That is the same trap our shrimp page describes, and guppies sit on the same side of it.

If your water is already hard, this kit tells you so once and you never think about it again. That is a good outcome for twelve dollars.

The honest costs. It tests hardness and nothing else, so it is a companion to a master kit rather than a replacement. Titration is fiddlier than a color card: drops one at a time, swirl, count, and losing count means starting over. Reagents expire. And the reading only helps if you are willing to act on it.

The correction, and deliberately second to the test, because adding it without testing is how people overshoot in the other direction.

A small amount in the filter or mixed into the substrate raises carbonate and general hardness steadily rather than in a jolt, which is how you want to move any parameter in a stocked tank.

It buffers pH upward at the same time, which reduces the drift that livebearers object to.

The honest costs. It is not a neutral substrate and is not sold as one — it changes water chemistry continuously, and how far it moves yours depends entirely on your starting water. It is the wrong default for a community tank and right only after a test said so. And it is a slow lever: add a little, wait a week, re-test. Emptying a bag in is a parameter swing.

Guppies feed at and near the surface and are enthusiastic to the point of being misleading — they will act hungry permanently, which is how a guppy tank gets overfed.

A flake is the conventional and correct staple here. What decides outcomes is the amount: what they finish in about a minute, once a day.

The honest costs. Flake is hard to portion precisely compared with a countable pellet, which matters because overfeeding is the commonest way a small guppy tank fouls. It loses nutritional value once opened, so a large tub is false economy for a 10 gallon tank. And no food compensates for a tank holding more fish than its filter supports — which, with guppies, is where this page is really pointed.

Plants in a guppy tank are not decoration, they are the variable that sets your fry survival rate — and therefore how fast the population grows.

Dense floating cover means more fry survive. Little or no cover in a tank with adults means most fry are eaten, which for many keepers is the preferred outcome. Either way the choice should be deliberate rather than accidental.

Hornwort is the easiest version: it floats, needs no planting, tolerates low light and grows fast enough to matter within weeks. It also consumes the nutrients that would otherwise feed algae.

The honest costs. It sheds needles, which end up in the filter intake. It grows fast enough to need thinning, and a tank left alone becomes a mat that shades everything beneath it. And if you do not want fry, dense cover is working against you.

Newborn guppies are a few millimeters long and a powered filter intake will take them. Whether that is a problem depends entirely on which outcome you want.

If you want fry, a sponge filter is close to mandatory. If you do not, a hang-on-back doing some of the population control for you is a legitimate choice, and this pick is the wrong one for you.

A sponge filter is also the gentlest option for long-finned males, who are poorer swimmers in current than their size suggests.

The honest costs. No pump, airline or check valve in the box, so the real purchase is three or four items, and the pump is the noisiest thing in the setup. No mechanical polish, so fine particles stay suspended. It is visible in the tank. And it is a nano device — on a stocked 20 gallon community tank it supplements a main filter rather than replacing one.

One sponge filter in a tank of this size is exactly what a pump in this bracket is for, and buying further up the range adds output you cannot use.

The honest costs. No airline tubing and no check valve included, and the check valve is not optional — without one a stopped pump siphons tank water onto the floor. No flow control, so an air control valve is a separate purchase if the bubbling is brisker than you want. And the diaphragm is the wearing part; expect to replace the unit rather than service it.

Most stocking mistakes are things you did. With guppies the stocking level changes without you doing anything, which makes testing a different kind of necessity.

A tank that was comfortably stocked in March can be carrying three times the bioload by August, and the first evidence is a nitrate reading climbing between water changes rather than anything visible.

The honest costs. It does not test hardness — which, on this page in particular, is the parameter you also need, so budget for both kits. It is slower and fiddlier than strips, the nitrate test needs the second bottle shaken hard and then a wait, and the color card is hard to read between adjacent shades under warm light. Reagents expire.

The skip entry, and it is a good tank being pointed at the wrong fish.

OATA specifies **at least 45 liters for a small group of the smaller species** — about 12 US gallons. A 5 gallon tank is well under half that, and that is the figure *before* the breeding starts.

The tall portrait footprint compounds it: less water surface per gallon than a conventional rectangle, which is the opposite of what a tank with a rising bioload wants.

For a betta, a shrimp colony or a snail tank this is a perfectly reasonable kit, and our nano pages recommend it as such. For guppies it is the purchase that guarantees the problem this page is about.

The honest costs of the skip. Nothing is wrong with the tank. If you already own one and have guppies in it, the answer is not to replace the fish — it is to plan an upgrade, keep the group all-male so the number stays fixed, and change water more often than the label suggests until you do.