The Best Fish for a Planted Tank

A goldfish can strip a planted 20-gallon to bare stems in a week, uprooting what it does not eat. The best fish for a planted tank do the reverse: they leave the plants alone, and they want the same soft, warm water most aquarium plants grow in. That overlap is the whole game. Pick fish whose temperature, pH, and hardness sit inside the plants' range, and the tank holds together.

The list below is five species that pass both tests: gentle on plants, and easy at planted-tank parameters (roughly 72 to 80 F, pH 6.5 to 7.5, soft to medium hardness). None is a plant eater, and all are sold as beginner fish. The catch is in the water chemistry, and I will get to where it bites.

The short version

• Planted-tank fish need two things: they do not eat or uproot plants, and they suit soft, slightly acidic, warm water (about 72 to 80 F, pH 6.5 to 7.5).
• Five that fit: harlequin rasbora, neon tetra, honey gourami, bronze corydoras, and otocinclus.
• Avoid plant-wreckers (goldfish graze and uproot) and hard-water livebearers if your plants and other fish want soft water.
• Otocinclus is the one trap here: it only survives in a mature tank (three-plus months) with steady algae, or it starves.

What "planted-tank safe" actually means

Two failures kill more planted tanks than any disease: fish that eat the plants, and fish kept at the wrong water chemistry. A planted-tank-safe fish avoids the first by design. Goldfish (Carassius auratus) graze soft leaves and dig up roots, so they belong in a pond or a 30-gallon-plus tank, not a scape. The toughest plants survive a goldfish (Java fern, Anubias, Vallisneria), but the delicate ones do not.

The second failure is quieter. A fish parked outside its parameters does not die on day one: it weakens over weeks, its color fades, and it catches whatever comes through. So planted-tank-safe also means the fish is comfortable at the temperature and hardness your plants want. Most low-tech planted tanks run 72 to 80 F with soft to medium water, which suits the five fish below.

The five fish that fit

Every number here comes from the compatibility database, so you can check the overlap yourself. Each of these stays small, stays peaceful, and stays off the plants.

Fish	Temp	pH	Hardness (dGH)	Group	Min tank
Harlequin rasbora	72 to 81 F	6.0 to 7.5	2 to 12	6+	10 gal
Neon tetra	70 to 81 F	5.5 to 7.0	1 to 8	6+	10 gal
Honey gourami	72 to 82 F	6.0 to 7.5	4 to 15	1	10 gal
Bronze corydoras	72 to 79 F	6.0 to 7.5	2 to 12	6+	20 gal
Otocinclus	72 to 79 F	6.0 to 7.5	4 to 15	6+	10 gal

The harlequin rasbora (Trigonostigma heteromorpha) is the forgiving one: a 1.5-inch schooler that tolerates parameter swings a neon will not, which makes it the best first fish for a planted 10 to 20 gallon. Keep six or more, or the school breaks up and they hide.

The neon tetra (Paracheirodon innesi) is the classic soft-water schooler at 1.2 inches, but read the range: pH 5.5 to 7.0 and hardness 1 to 8 dGH. That is soft, acidic water, and it sets the neon against any hard-water tankmate. Keep six or more.

The honey gourami (Trichogaster chuna) is the centerpiece that will not bully: a peaceful 2-inch labyrinth fish, unlike its aggressive cousins. One is enough, and it works in a planted 10-gallon. Bronze corydoras (Corydoras aeneus) work the bottom for leftover food in groups of six, but they need smooth sand, not sharp gravel that wears their barbels, and a 20-gallon footprint. For a 10-gallon, the one-inch pygmy cory (Corydoras pygmaeus) is the right substitute. Otocinclus (Otocinclus sp.) is a true algae-eater that never touches healthy plants and stays under 2 inches, and it is the one trap on this list, covered below.

Match the water, not just the fish

The single most common planted-community mistake is mixing soft-water and hard-water fish in one tank. A neon tetra wants pH 5.5 to 7.0 and 1 to 8 dGH. A guppy (Poecilia reticulata) wants pH 7.0 to 8.0 and 8 to 20 dGH. There is almost no overlap, so one of them is always in the wrong water.

Your tap water decides this before you buy a fish. Hard, alkaline tap (GH above 12, pH near 8) suits guppies, platies, and endlers, and plants like Vallisneria (Vallisneria spiralis) that handle 6.5 to 8.5 pH. Soft tap suits neons, rasboras, and most stem plants. Test your water first, then pick the fish that already live where your water sits.

Fighting your tap chemistry is a losing game in a low-tech tank. Chasing pH with additives swings it and stresses everything. It is easier to match the stock to the water than to rebuild the water for the stock, and the wider question of which plants pair with which fish is its own topic (see aquarium fish and plant compatibility).

The honest part: where planted tanks go wrong

The otocinclus is where good intentions kill fish. It eats biofilm and soft algae, and a new tank has almost none, so an oto added in the first month slowly starves. Only add otocinclus to a tank that has run three-plus months and grows a steady algae film. Even then, buy six, because they are social and ship stressed.

The second trap is stocking for the plants and forgetting the bioload math. A planted tank filters better than a bare one, but plants are not a filter you can overstock behind. Five fish species at once in a 10-gallon is too many: pick one schooling fish (six to eight), one centerpiece, and a small cleanup crew, and stop there.

The third is fin-nippers. Tiger barbs and serpae tetras shred the trailing fins of a gourami, and a torn fin opens the fish to fin rot. Keep known nippers out of a peaceful planted community, whatever the stocking chart says.

Frequently asked questions

What is the best fish for a small planted tank?

For a planted 10-gallon, a school of six to eight harlequin rasboras or ember tetras with a honey gourami centerpiece is hard to beat. All three stay small, ignore plants, and share the same 72 to 82 F, slightly soft water. Add a few snails or a small shrimp colony for cleanup and the tank is stocked.

Do any fish eat aquarium plants?

Yes. Goldfish and most large cichlids graze and uproot soft plants, and silver dollars strip them fast. If you want those fish, stock only the toughest plants (Java fern at 68 to 82 F, Anubias, Vallisneria), which grow from rhizomes and leathery leaves that fish leave alone.

Can I keep shrimp with planted-tank fish?

Often, if the fish are small and peaceful. Adult cherry shrimp (Neocaridina davidi) live safely with pygmy cory, ember tetra, and otocinclus, though most fish pick off baby shrimp. A betta or anything over 2 inches will hunt them, so match the shrimp to calm tankmates and heavy moss cover.

How many fish can a planted tank hold?

Fewer than the old inch-per-gallon rule suggests. A planted 10-gallon holds one small school (six to eight fish under 1.5 inches) plus a centerpiece and cleanup crew, comfortably. Understocking keeps the water stable and lets the plants keep up with the waste.

Once you know your tap water and your tank size, the rest is matching overlaps: temperature, pH, and hardness that all the stock shares. Run your numbers through the build planner for a stocked, balanced list, cross-check any species in the livestock database, and if a betta is your centerpiece, read betta tank mates before you add anything else. For the wider map, the species-compatibility guides cover what pairs with what, and what fish can live with shrimp goes deeper on the shrimp question.