Catappa leaves: grazing surfaces without overloading the tank

Catappa leaves provide extra grazing surface and may tint the water brown. They remain decomposing organic material. Start with a small clean piece, observe the tank and add more only for a reason. A leaf cannot replace an established filter or water testing.

Prepare and introduce the leaf

• Use leaves from a source suitable for aquarium use. Rinsing does not establish that unknown pesticides are absent.
• Rinse away loose dust. Initial floating is acceptable; secure the leaf safely if necessary. Briefly pouring hot water over it may speed soaking, but cannot certify an unknown treated leaf as safe.
• Record the addition. Avoid changing the food ration and several other additions at the same time, or the response becomes difficult to interpret.

There is no universal leaf count per litre

Leaf size, dry weight and decomposition rate differ. Filter maturity, temperature and existing organic load matter too. Follow the actual product instructions without treating its dose as a proven safe limit for every tank. Delaying the addition or starting with less in a small or young tank is a conservative editorial judgement.

Microorganisms may colonise the surface as the leaf breaks down. Softening alone is therefore not a reason to discard it. Remove excess decaying material if the water clouds, debris accumulates, behaviour changes or ammonia/nitrite becomes detectable. Also check aeration and other causes; brown colour alone says nothing about water safety.

Tannins, KH and species choice

Seachem describes the release of tannins and organic compounds. The pH response depends partly on buffering. In soft, low-KH water, measure before combining several leaves, wood or other botanicals. Do not use catappa as a dosing method to reach a target pH. Acidifying additions are not automatically beneficial for warm, alkaline-water Cardinal shrimp from Sulawesi; fan shrimp do not receive their required suspended food simply from a leaf placed on the bottom.

Do not add a large new leaf load just before a holiday. An established grazing surface is more predictable than a new organic addition. For deaths or suspected contamination, use the water and problem route; adding leaves is not a substitute for investigation.

Sources and scope

• Seachem: Catappa Leaves Md
• US EPA: Dissolved oxygen
• SRAC 464: Interactions of pH, Carbon Dioxide, Alkalinity and Hardness
• Aqueon: Freshwater shrimp, bamboo-shrimp feeding

The manufacturer describes the product and its use. Our conservative sequence is an editorial choice, not an experimentally established safe dose for all dwarf shrimp. We make no disease-treatment claim. The Aqueon source is used only for fan shrimp capturing suspended food from a current.