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Care guide · Freshwater snails

Diadem nerite snail

Clithon diadema

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The diadem nerite snail (Clithon diadema) is a small nerite associated with estuaries and coastal waters in Southeast Asia. Adults occur in fresh and brackish water, but larval development requires saltier water and does not proceed in an ordinary freshwater aquarium. A mature tank with natural growth on stone, wood or glass is therefore important. Reliable species-specific aquarium limits and a responsible minimum tank volume are not established well enough; this guide makes that uncertainty clear instead of implying false precision. The 2024 breeding study describes specialist salinities for reproduction, not a recipe for a community aquarium. We explain what is known, how to reduce food-shortage and escape risks, and why no unverified product or tankmate recommendations appear here.

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At a glance

Temperature
20–30 °C
pH
7.0–7.2
Diet
Herbivore
Adult size
Approximately 1–1.5 cm
Temperament
Peaceful

About this species

Clithon diadema (Récluz, 1841) belongs to Neritidae. MolluscaBase/WoRMS accepts this scientific name. Older sources may use Nerita (Clithon) diadema or Neritina diadema. The shell may carry spines and yellow, orange, dark or spotted patterns, but appearance and trade names alone do not always ensure identification. Fishipedia gives about 1–1.5 cm; a breeding study measured adults averaging about 9 mm shell length. These are different measures, not a guaranteed maximum.

Natural habitat

Species accounts associate the diadem nerite with Indonesia, the Philippines and Thailand, including estuaries, mangroves and lower stream or river reaches. These habitats experience changing salinity and offer hard surfaces where growth can develop. The origin of aquarium-trade individuals is not necessarily known. Being sold as a freshwater snail also does not mean its entire life cycle occurs in fresh water.

Aquarium and layout

Use a stable, biologically mature aquarium with stone, wood or other hard surfaces that can support natural growth. A newly set up or heavily cleaned tank may not provide enough food. A reliable species-specific minimum volume has not been established; match stocking to available grazing surfaces and natural growth rather than a single litre figure. A secure lid helps prevent escape. Acclimate slowly and do not force a transition between very different salinities.

Water conditions

Fishipedia lists 20–30°C as a broad habitat temperature range and cautions that aquarium advice is estimated. It is not an experimentally established optimum. We found no sufficiently reliable species-specific pH, GH or KH limit to publish as a firm aquarium target. Avoid abrupt changes and keep water clean and stable. Salinities in the propagation study are breeding conditions, not a reason to add salt to an ordinary community aquarium.

Behaviour and group size

Fishipedia describes the species as solitary and peaceful. Controlled tests with specific aquarium tankmates are unavailable. Treat cohabitation as a cautious choice: avoid animals that eat snails, pull at them or displace them from hard grazing surfaces. After introduction, check that the nerite can attach and graze normally. There is no demonstrated need to keep several diadem nerites as a group.

Feeding

Species accounts describe adults grazing on hard surfaces. The 2024 breeding study compared diatoms and other algae with, among other diets, commercial prawn feed for adult broodstock. In that experiment, diatom-fed groups produced more egg capsules than groups fed commercial feed or sea lettuce. This does not prove that an arbitrary aquarium product is complete or reliably accepted. Provide a mature aquarium with natural growth and ensure enough remains available. We do not link a catalogue product without species-specific evidence.

Breeding

The sexes are separate and egg capsules may be attached to hard surfaces. Capsules do not mean juveniles will appear. In a controlled study embryos did not hatch at 0‰; hatching occurred above 0‰, while capsule production was best at 15–20‰ with diatoms. Larvae were raised at 25‰ under specialist conditions. This requires a dedicated breeding setup and is not advice for a mixed freshwater aquarium. Do not add salt to make eggs hatch.

Keeping with fish

No controlled trials with named fish tankmates were found for this snail. One conditional comparison is the medaka (Oryzias latipes): the temperature advice in the existing species guide overlaps only around 20–22°C and pH 7–7.2. Consider this pairing only if your aquarium remains stable there, mature grazing growth is available and the fish leaves the snail undisturbed. This is a cautious profile comparison, not a proven safe pairing. Avoid known snail-eaters and larger fish that may attack the snail.

Keeping with other invertebrates

Existing public records do not confirm sufficiently well-supported pairings with named shrimp, other snails, crabs or crayfish either. Predatory snails and animals that eat or seize snails pose a clear risk. We leave the relation cards empty instead of inventing suitable species. Check the needs of each proposed tankmate and avoid competition for limited natural growth.

Exoskeleton, shell and minerals

A snail does not moult like a shrimp. Shell damage or erosion can have several causes, and appearance alone is not a diagnosis. Check water values, whether the snail can reach enough natural growth and whether there have been sudden changes. Do not add minerals, calcium or salt without evidence; adjust water chemistry only gradually and for a clear reason. Avoid copper-based treatments unless confirmed safe for snails.

Possible problems

Key concerns include insufficient natural growth in a young or overly clean tank, escape, sudden salinity changes and confusing egg capsules with successful reproduction. The scientific paper also warns of possible ecological effects from excessive wild collection; it does not assign a formal conservation category here. Fishipedia reports the species as not evaluated on the IUCN Red List. Ask about source and captive-bred status, and never release aquarium animals, eggs, plants or water into the wild.

Sources & review

This care guide draws on several specialist sources and was last checked on .

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