Cryptocoryne Care: Wendtii, Parva, and Other Easy Crypts

Cryptocorynes, or crypts, are rosette plants that grow from a crown in the substrate. Wikipedia notes the genus is native to tropical India, Southeast Asia, and New Guinea, and that some species, such as Cryptocoryne wendtii, are said to be among the most versatile aquarium plants. A few species are demanding, but the ones most shops sell are among the easiest rooted plants you can grow. This guide covers the easy species, how to feed them, and how to handle their best-known habit: melting.

Cryptocoryne quick facts

Difficulty, light, CO2, and growth ratings are Tropica's. Tropica's data box for parva lists 5-10+ cm, while its description calls it "only 3-6 cm tall"; Aquasabi says it mostly reaches 2-5 cm in the aquarium.

What are the easy crypt species?

• Cryptocoryne wendtii. A very variable species from Sri Lanka, according to Wikipedia, sold in green, brown, and red forms. Tropica rates 'Green' easy and notes that in open space the leaves almost lie on the bottom. 'Tropica' has dark, hammered leaves and suits small tanks. 'Mi Oya' is a red-brown form that Tropica says comes from the Mi Oya river in Sri Lanka.
• Cryptocoryne x willisii. Tropica says it was long sold under the wrong name, C. nevillii, and that after a quiet first period it produces plenty of runners and forms a compact group.
• Cryptocoryne parva. Tropica calls it the smallest of all crypts. It grows slowly and needs more light than other crypts because its leaves have almost no leaf blade underwater. Tropica rates it medium difficulty, while Aquarium Co-Op sells it as easy. It is the crypt to choose for a low foreground lawn, if you are patient.

How much light do crypts need?

Most need very little. Tropica rates wendtii 'Green', 'Tropica', 'Mi Oya', and x willisii as low light, and says wendtii 'Green' thrives in shady places in the aquarium. Aquarium Co-Op recommends low light of about 10-20 PAR for its wendtii and parva.

Parva is the exception. Tropica rates it medium light and says it must never be shaded by other plants. Aquasabi says it needs more light than many other crypts, but that medium light and an open position are enough. Aquarium Co-Op still lists 10-20 PAR, so it can survive in a dimmer tank, but expect slower spread. The light intensity and duration guide explains how to judge your light.

Do crypts need CO2?

No. Tropica rates every crypt in the table as low CO2, and Aquarium Co-Op lists the requirement as none. Aquasabi notes that parva benefits a great deal from CO2 and nutrients in the substrate, and Buce Plant says CO2 can help a melted crypt recover, but neither is required for the wendtii group. See low-tech vs. high-tech planted tanks if you are deciding on CO2.

What temperature and water do crypts need?

Aquasabi lists a temperature tolerance of 15-30 °C, pH 5-8, and general hardness of 0-30 °dGH for wendtii 'Green'. For parva it gives 15-28 °C, with an optimum of 23-28 °C. Tropica says wendtii 'Green' and 'Tropica', like most Sri Lankan crypts, grow well in hard water. Tropica also notes that 'Mi Oya' comes from streams where temperatures exceed 30 °C.

The bigger issue is stability. Aquarium Co-Op and Buce Plant both say crypts are sensitive to changes in their environment, including swings in temperature, water chemistry, and water change routine. Steady conditions matter more than any particular value.

Do crypts need root tabs?

Usually, unless they are in a nutrient-rich substrate. Aquarium Co-Op says crypts absorb a lot of nutrients from the ground, and that if leaves yellow and die after a couple of months, the plant needs more root tabs. Tropica recommends its nutrition capsules for Cryptocoryne and other plants with sturdy roots, placed close to the roots, and says capsules speed up parva's slow growth. Buce Plant recommends a nutrient-rich substrate for root feeders.

In inert gravel or sand, push a tab into the substrate near each crypt or group of crypts, following the product's spacing.

Seachem

Seachem Flourish Tabs (10 tabs)

Model: Flourish Tabs

Best for

Trying root tabs in a small tank with swords, crypts, or other root feeders.

Skip this if

Your substrate is a fresh nutrient-rich aquasoil, or your tank has few rooted plants.

Type

Gravel bed (root zone) supplement

Contains

Trace elements, amino acids, vitamins (incl. iron, manganese, magnesium, calcium, potassium, inositol, choline, B12, biotin)

Phosphate / nitrate

None

Dose

1 tab per 10-15 cm (4-6 in) radius; a 10-gallon tank uses 6 tabs

Replacement

Add new tabs every 3-4 months

Coverage

A 10-tab pack treats a 12 x 30 in plant bed twice

Strengths

• Feeds rooted plants at the root zone.
• Long interval: replace every 3-4 months.

Limitations

• Contains no nitrate or phosphate.
• A 10-tab pack covers only a small bed.

Check Price on Amazon ↗ (opens Amazon in a new tab)Specs checked 2026-10-05. Prices and availability are on Amazon.

Seachem directs one tab for every 10-15 cm (4-6 in) radius, pushed midway into the gravel bed, with new tabs every three to four months. Seachem says the tabs contain no phosphate or nitrate, so a tank with very few fish may also need a liquid fertilizer. Skip root tabs while your crypts are in fresh, nutrient-rich aquasoil.

For how tabs fit with liquid dosing, see root tabs vs. liquid fertilizer. Growing in sand? How to grow aquarium plants in sand covers tab placement and depth.

How do you plant crypts?

Tropica's planting guide gives the method for rosette plants such as Cryptocoryne:

1. Trim the roots to about 4 cm so you can remove the pot and mineral wool.
2. Split the cluster into individual rosettes.
3. Remove the old outer leaves.
4. Plant the rosettes singly or in groups.

Tropica suggests planting with the water only about 2 cm above the gravel so you can see what you are doing, and keeping the plants moist with a spray bottle. For parva, Tropica says to plant individual plants a few centimetres apart; after about six months they form a low, joined group.

Once planted, leave crypts where they are. Aquarium Co-Op says a crypt recovers best when it is not moved again.

Why is my crypt melting?

Crypt melt is the fast collapse of leaves, often within days. Buce Plant describes leaves browning or yellowing and then turning translucent. There are two main triggers:

• New plants. Aquarium Co-Op and Buce Plant both explain that nurseries grow crypts emersed, with leaves in air. Once submerged, the plant replaces those leaves with underwater ones, and the old leaves often melt.
• Changes in an established tank. Aquarium Co-Op lists shifts in water quality, water change frequency, location, lighting, fertilizer dosing, temperature, and CO2 injection as triggers.

What to do:

1. Cut melting leaves at the base. Aquarium Co-Op warns that rotting leaves can cause nitrogen spikes or algae.
2. Leave the roots alone. Do not pull the plant up to check it.
3. Wait at least three to four weeks for new shoots, as Aquarium Co-Op advises. Buce Plant says new leaves usually appear within a few weeks if the roots are healthy.
4. Once new growth appears, make sure the plant has root fertilizer and adequate light.

One exception: Buce Plant advises against trimming the leaves of Cryptocoryne parva, which usually does not melt like other species and may not bounce back.

Our full guide to aquarium plant melt covers how to tell normal melt from a problem, and the plant problem checklist walks through the checks at the tank.

How fast do crypts grow, and how big do they get?

Tropica rates wendtii 'Green' and 'Tropica' as medium growers, and 'Mi Oya', x willisii, and parva as slow. Aquarium Co-Op describes wendtii as a slow grower that needs patience between trims. Aquasabi notes that wendtii 'Green' starts growing relatively quickly compared with other crypts. Tropica says x willisii needs patience in its first month before it starts producing runners.

Size depends on the variety and conditions; Tropica's figures are in the table above. Wendtii 'Mi Oya' is the largest of the group at 20-30+ cm. Aquarium Co-Op gives about 6-8 inches (15-20 cm) for its wendtii 'Green'.

How do crypts spread?

By runners and side shoots. Wikipedia says C. wendtii is propagated by runners, and Aquarium Co-Op explains that crypts send out a horizontal runner with a plantlet at the end, or grow small offsets beside the parent. Cut the plantlet from the runner, or gently split off the offset, and replant it. Aquasabi notes that parva forms side shoots directly on its rhizome as well as runners.

You do not need to do anything for a group to fill in. Leaving runners in place is how a single crypt becomes a clump.

Other common crypt problems

• Yellowing older leaves months after planting. Aquarium Co-Op links this to root feeding; add or replace root tabs. Our guide to why aquarium plants turn yellow explains how to read yellowing patterns.
• Slow or stalled parva. Check that taller plants are not shading it, as Tropica warns, and that it has root nutrition.
• Repeated melt in an established tank. Look for a recent change in light, CO2, temperature, or water change routine, and make future changes gradually, as Buce Plant's advice on consistency suggests.
• Algae on leaves. If algae coats crypt leaves, the planted tank algae troubleshooting guide covers the likely causes.

Which tanks suit crypts?

• Low-tech tanks. The wendtii group and x willisii need low light and no CO2. See aquarium plants that don't need CO2.
• Betta tanks. Our planted betta tank guide includes wendtii 'Mi Oya' as a midground pick.
• Shrimp tanks. Low light and no CO2 suit a simple shrimp setup. Check that any root tab or fertilizer is suitable before using it around shrimp; see shrimp in planted tanks.
• Tanks with Anubias and Java fern. Crypts fill the substrate below hardscape plants. See our Anubias care guide and Java fern care guide.

Common mistakes

• Throwing out a melted crypt while its roots are still firm.
• Pulling a crypt up to check on it, which restarts the adjustment.
• Growing crypts in plain sand or gravel with no root fertilizer.
• Shading parva with taller plants.
• Making several big changes to light, CO2, or water at once.
• Trimming parva leaves the way you would trim a melting wendtii.

Next steps

• Read aquarium plant melt: what's normal and what needs fixing if your crypts are collapsing.
• Compare feeding routes in root tabs vs. liquid fertilizer, or browse fertilizers by need.
• Pair crypts with hardscape plants using our Anubias and Java fern care guides.
• Ready to buy one? Our beginner aquarium plants to buy online includes a potted Cryptocoryne wendtii 'Green', with what the listing ships and how to plant it on arrival.
• Choose a base for root feeders with how to choose aquarium substrate and size it with the substrate calculator.
• Browse more species on the aquarium plants hub, or plan a tank with the setup finder.