Riccia Fluitans/Moss Mats – Fishing Line and plastic grid/cloth method

There are many different methods to create flat sections of moss, riccia, or other plant life that doesn’t typically carpet or grow in such a form naturally. These mats can be quite effective when fully grown, and allow the easy control and use of new colors and textures in the planted tank. Takashi Amano is credited with first using riccia fluitans, aka crystalwort, in such a scenario. Since, many different types of plants have been experimented with, some with more success than others. Here’s what you’ll need to make a mat:

The Plant

Mats work best with fast growing species that split in many different directions as they grow.  Common choices include Riccia fluitans/ CrystalwortJava MossChristmas MossPellia liverwort (Monosolenium tenerum), or Fissidens.

The Mat Material

Any material which can withstand being under water without decay or contaminating the water (many plastics, stainless steel 316, etc) can bee used for this. Common choices include nylon netting from craft stores, plastic grids from craft or hardware stores, metal meshes, or re-used material from bath poofs, filter media bags,… The material needs many openings that are large enough to let in light and allow the plant to grow through while being small enough to hold back the initial portion of the plant. Be careful if using metal – stainless steel 316 is the most common choice for fish tank use, and those edges can be sharp!!


Any string or thin material that won’t degrade under water that can fit through the holes of the chosen material works for this step. Fishing line is a common choice, as it is hard to see and easy to use. The thinner the line, the less visible and easier to work with. Riccia Line is usually just a green tinted fishing line, such that it blends in quite well immediately. Nylon thread also works well for this and is available in a variety of colors. If you steel mesh for the material and attaching the mat directly to wood or an object, then thread or line won’t usually be needed.

My riccia and moss mat process using filter media bag and fishing line:

Collect the portions of riccia, moss, etc to be used and plan out the size of the mat. The plant will need to be placed between two layers of the mat material, so either cut two identical pieces for the top and bottom, else, if the material is easily folded, cut a single piece that can be folded to give the right mat shape. Giving yourself some extra room around the edges that can be trimmed can make sewing together the mat easier.

Spread the plant portion over the mat material that will form the bottom half of the mat, as below.

A uniform layer just thick enough to cover the entire mat bottom is ideal. If the layer is too thick, portions of the plant often die or decay due to lack of light and water flow. Put the top half of the mat into place, and use the thread/line to tie small knots every half inch or more along the open edges.

I keep the mat wet with tank water throughout the process. Any sections of the plant that dry out can become damaged and die rather than grow into the mat.

I’ll be sure to post updates soon on how these mats are growing out in my new 7 gallon setup! I also ordered some stainless steel 316 wire mesh/screening this week, and will be making some mat portions with that as well. I’ll post on it once I’ve found a good method.

2 thoughts on “Riccia Fluitans/Moss Mats – Fishing Line and plastic grid/cloth method

    • Let me know how it turns out! I recently got some stainless steel mesh, and my riccia is growing out of it like crazy. It was harder to setup, but easier to use. I haven’t tried it with moss yet, but I will soon.

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