Catappa or often called Indian almond leaves are very popular in the aquarium hobby. They have multiple different benefits and many people choose to put them as an extra in their tank. If you plan to use catappa leaves for your (betta) fish you might wonder how long catappa leaves actually last before breaking down.

Catappa leaves will take 3-5 days to sink, after this they will release most of their tannins and start breaking down. Once sunken, they usually last for 1-2 months in your aquarium before breaking down. 

Methods of using catappa leaves

The most common method of using catappa leaves is putting them completely in your tank. The dried leaves will first float and sink after a few days. Some people remove the nerves before putting them in which can cause the leaves to lose a part of their firmness and last less long. 

Apart from putting the leaves directly in the tank, you can also create Indian almond leaf extract. This is water with a very high amount of tannins in it, which makes it very concentrated. This way you can just store it in bottles and easily pour some extract in the water with immediate results.

Why use Indian almond leaves?

Indian almond leaves (IAL) are frequently used in a lot of tanks and you can recognize them by their big size and once in the water causing a brown water-colour. 

However it is thrown around that catappa leaves are beneficial to your fish, you probably want to know why exactly IAL benefit fish and why you would want to add them. How long they last precisely depends on different factors such as the quality of leaves and what fish you have.

  • 1. The useful tannins and chemicals

The most important and known reason you really want to add catappa leaves is because of their unique chemical composition. By putting them in your tank, these tannins and chemicals such as alkaloids and flavonoids are released and added to the water.

These tannins make your fish stronger and can even make your fish more resistant towards diseases and infections. They are often used to cure diseases such as fin rot or dropsy. Because of the small amount of acids in them, it’s possible they also lower your pH.

Most evidence is anecdotal based on the experience of fish-keepers who claim seeing these improvements when using them. However, there have been done multiple studies on the effects of the leaves on growth-rate, survival rate etc. Read more about catappa leaves for betta fish→

  • 2. They make your tank more tank more natural

The habitats of many aquarium fish are so-called blackwater streams. This are rivers or pools with dark-brown water caused by the tannins in organic materials breaking down. When the leaves are sunken, they work like a bag of tea and will color the water brown/yellow. 

For example, where bettas live in the wild the substrate fully consists out of leafs and organic materials, with pH being mostly very low between 4 and 6. Mostly these pools are dark of color, not by pollution but because of the organic materials in the substrate who release tannins. On top of that, the leaves and branches provide lots of cover for betta fish to hide or create their territory.

In South America this will not be catappa leaves, but other leaves with comparable effects.

By adding leaves or their extract to your tank, you recreate a part of most fish natural environments by adding extra cover and color. If you don’t like the color of the leaves, you can also boil the leaves (creating an extract) and afterwards putting them in. Here’s a beautiful example of that. Keep in mind that you will not receive the beneficial effects of the tannins. 

  • 3. Extra food for fish and shrimp

Catappa leaves are very similar to what most plant-eating fish eat in the wild and leaves make up a part of their natural diet. In the wild most shrimp and pleco species (herbivores) eat algae growing on stones and wood, and sometimes a small part meat based foods. 

They contain multiple different good minerals and chemicals. Although most of them will be released to the water, your fish can get some extras by scraping parts of the leaves. This will also add a lot of fibres to the digestive system which are beneficial for the further digestion of the fish. 

After the catappa leaves are in your water, there will often grow small algae and microorganisms on them, this makes them even more attractive to plant-eating fish species who’s diet in the wild consists mostly out of algae.

Fish that eat catappa leaves

Shrimp is the most common example who love catappa leaves and when you add catappa leaves to your water with shrimp they will start feasting on it in no-time. After a couple of days you will remain with only a maze of nerves. Most vegetarian fish species absolutely love eating catappa leaves and the algae on them too. Think about otocinclus and herbivore Loricariidae such as Bristlenose plecos and Panaqolus species.

What fish benefit from catappa leaves?

The fish where we talk about on this blog, betta fish and especially wild betta fish certainly benefit from catappa leaves. All fish living in South-America love them too and naturally live in low water with a low pH such as blackwater rivers. Actually, I’m pretty confident saying that most fish in your aquarium would benefit from the tannins catappa leaves add to the water. 

Although catappa leaves can be beneficial for a lot of fish, some benefit more than others. Here are some of the fish that certainly benefit from them.

  • Betta fish  

I wouldn’t be a real betta blogger if I didn’t put the well-known betta first t :). Betta fish are some of the most popular fish who benefit a lot from catappa leaves in the tank. Wild betta habitats are usually packed with a lot of organic material on the bottom and the catappa tree is native to Thailand and Southeast-Asia. This makes catappa leaves perfect for replicating their habitat and adding the benefits they also get in the wild. Domesticated betta fish do not absolutely need catappa leaves, but for wild betta fish it is recommended since they are less used to tap water and get stressed more easily.

  • Angelfish 

They originate from the Amazon river system and prefer slow and rather shallow streams. This makes the habitat mostly sour and covered with lots of trees hanging over, who shed their leaves causing coloring of the water. Angelfish are a popular blackwater fish who go well in setups with lots of natural cover and a lower pH.

  • Corydoras 

Corydoras species naturally live in South American streams in the Amazon river system. Because they prefer smaller streams without too much current with lots of cover in the form of overhanging trees there are lots of organic materials in the natural habitat of cory catfish.I have bred and kept multiple Corydoras species myself and used the leaves often to stimulate spawning and hatch eggs, that tend to be sensitive towards moldiness.

  • Apistogramma

Apistogramma sp. are one of the more-known blackwater fish. Wild habitats are similar to those of Corydoras, in shallow and covered streams with some plants. On the bottom there are lots of leaves and organic materials such as nut shells. It’s often said that Apistogramma are cave-breeders, but they actually bread in the substrate and leaf litter on the bottom. This makes catappa leaves perfect for them and Apistogramma will thrive in blackwater setups. If you put some big leaves in your tank, covered well they will probably spawn on here.

  • Shrimp

Shrimps love eating them and sitting on them grazing on the micro-organisms and using them to hide. Caridina shrimp also love a lower pH.

Catappa leaves for wild caught fish

Most fish you buy are captive bred and will be adapted to the normal tap water. This makes catappa leaves for them not absolutely necessary, and more an extra edition. For fish that are caught in the wild however catappa leaves are strongly recommended. The natural habitats of a lot of aquarium fish are loaded with leaves and wild caught fish aren’t addapted to regular tap water and conditions captive bred fish live in.

If you don’t add extra cover or tannins to the water your wild caught fish might stress out more. This can cause your fish getting sick or you just can’t enjoy seeing them because they only hide. Wild caught fish are mostly less colourful and the tannins will let the fish colour up way more. 

Not all fish benefit from catappa leaves, some fish don’t like soft or tannined water such as african cichlids. They are not deadly or very harmful, but just won’t benefit your fish and aren’t native in habitats of some aquarium fish. However they can be beneficial as a temporary cure for diseases it’s not recommended using them permanently. Please do your research before using catappa leaves in your tank to see if they are suitable for the fish you have.

Why leaving catappa leaves in your tank?

After a couple of days the leaves will have released all of the useful tannins, job done which makes them useless, right? Not at all! The leaves actually stay useful for as long as they’re around. 

If you have some fish or shrimp that eat catappa leaves, they will get a lot of useful minerals and nutrients from them, even after they released all the tannins. 

The leaves also provide a great shelter and breeding environment for a lot of fish species such as Apistogramma and corydoras species. I personally like the natural look of the leaves in my tank and recreating how my fish live in the wild. This way my fish feel more comfortable and I prefer a more natural look over a clean and brushed off look.

If you’ve created catappa leaf extract you can just put them afterwards in for your fish to feast on or to recreate a natural habitat. If you do not like the brown water color but do like the look of the leaves this is an option too. You will not receive the useful tannins however.

Fish that eat catappa leaves

Catappa leaves contain multiple different good minerals and chemicals which makes them a very good source of food for a lot of fish and shrimp. Although most good chemicals will be released to the water, your fish can get some extras by scraping  and eating parts of the leaves. This will also add a lot of fibres to the digestive system which are beneficial for the further digestion of the fish. Apart from shrimp, I have seen numerous fish species feast on catappa leaves.

After the catappa leaves are in your water, there will often grow small algae and microorganisms on them, this makes them even more attractive to plant-eating fish species who’s diet in the wild consists mostly out of algae.

Apart from shrimp there are numerous other fish that eat catappa leaves, or the organisms growing on them. Think about otocinclus and a lot of pleco species such as clown and bristlenose plecos.

The quality of your catappa leaves.

The quality of your catappa leaves has a very big effect on how long your leaves last. Low quality leaves cause cloudiness and don’t have the same positive chemicals and tannins in them. They are processed badly and often unnaturally dried. The trees could also be treated with certain antibacterial products to make them look nicer.

I have tried multiple cheap chinese leaves, and when making extract or putting them in my tank I always created a cloudy substance. I also found that the leaves are way less firm and break down into pieces way faster.

By choosing high quality leaves you are certain your fish get all the useful tannins, and that they are firm and long-lasting without causing cloudiness. The price is often a good indicator and cheap leaves are usually not a good choice. I advice against cheap leaves on sites like Aliexpress.

I have tested out some different brand leaves such as Sera but those are often too expensive for the amount of small leaves you get. I prefer buying mine on amazon and you can find some good catappa leaves on Amazon