The Secret to successful Fish breeding — Sphagnum Moss

It helps to keep an eye out for tips from the breeding Gurus. I recently found this gem offered by American fish enthusiast, Ted Judy, and it is all about Sphagnum moss as a breeding medium.

So please note, this is not about peat moss, not about the lowering of pH, adding tannins, or anything else one can do with the mostly decomposed sphagnum peat moss we are all familiar with.  This is about the plant that could become decomposed peat moss, were it permitted to rot in the bottom of a bog for an eon or so.

Ted Judy explains the procedure as follows:  

“Sphagnum peat starts life as sphagnum moss, which grows in dense clumps at the surface of peat bogs.  Each year the plants die back in the winter and the dead leaves and stems sink into the bog.  New growth emerges the next spring over the now decaying plant matter, and this process is repeated year after year after decade after century.  Eventually the decomposed plant fibers buried deep in the bog create an acidic environment that halts further decomposition.  The peat that we use for lowering pH is mined from these bogs.  The upper layer of living moss is also harvested… for hanging plant baskets.

I purchase bales of long-fiber sphagnum moss at my local nursery, where it is sold as a decorative accessory for potted plants or for lining the bottom of hanging baskets of annuals.  There are several uses for the moss in the fish room too.


Preparing the Moss for General Use

Long-fiber moss is packaged dry and mixed with a lot of twigs and dirt that you will not want.  The trick is to clean the brittle moss without breaking it into small particles.

I prefer to start the cleaning process with a boiling water soak.  A mass of dry moss will lose volume when it is wet, so start with a volume at least 1.5 times larger than what you want to end with.  Place it in the bottom of a bucket and pin it down with a large rock (or something else suitably heavy).  Pour boiling water into the bucket until it just covers the moss, and then let it sit over night.

Remove the stone the next day, and decant the water.  The tedious job is to now pick through the moss to separate the long fibers from the sticks and dirt.  Another option is to add water back to the soaked moss, stir it vigorously to separate the fibers in the clump, let everything settle and then reach in and gently pull out the fibers.  Shake them a bit as you pull them out of the water to get the sticks to float away and the dirt to fall off.  Regardless of how you do it, the goal is to get a mass of moss that is free of debris.  Once it is clean you can use it immediately, or you can set it out to dry again for future use.  The next time you soak it you will not need to clean it.


I learned about long-fiber sphagnum moss from a killi-keeper who had a reputation for being the laziest breeder of all time.  His method for breeding mop-spawning killies is to fill a 1-gallon aquarium ½ deep with long-fiber sphagnum moss, put in two or three pairs of fish, feed them well and wait until he sees fry in the bottom of the tank hiding in the moss.  Then he transfers the adults to a virgin breeding set up and let them start all over again.  The moss is left in the fry tank until the fish are old enough to sex.  Then he starts pulling out pairs to sell or put into auctions.  Eventually, the killifish start spawning again and the breeder has another generation of killies to work with.  All the west African genera (Aphyosemion, Diapteron, Fundulopanchax, etc…) will happily breed in this manner.


Egg-scattering Tetras, Barbs and Danios

I use a set up similar to the killi tank to breed egg-scatterers.  I start with a layer of moss 2-3” deep in tank with whatever water I want (hard, soft, acid, etc…), and then put the females in for a few days to build up some eggs.  I do a partial water change at the same time that I add the males, which is always in the evening just before turning off the lights.  The only problem with spawning these fish over moss is that it is virtually impossible to see the eggs, so I choose to let the breeders stay in the tank for several days to spawn.  Sometimes I will see larvae in the moss and know it is time to remove the adults.  If no fry appear after a week or so, I will take the adults out and start looking for fry.  Most of the time fry will appear.

A couple species that were NOT successful over moss (or less successful that using an egg grate) have been the celestial pearl danio, Danio margaritatus  and the glowlight danio, D. choprae ; but both those species are master egg eaters, so I suspect that they were eating them as fast as they were laid.  The South American yellow emperor tetra, Hyphessobrycon ocasoensis, was hard for me to produce in any great numbers until I tried them with moss.  The adults are very shy and hide all the time, so a big pile of moss to dive into is the perfect habitat for them.  Over a plastic grate I rarely got more than a dozen eggs to hatch, but a single pair left in moss for a week produces 50+ fry.


Corydoras Catfish

I am not a gifted cory breeder.  If I can get the fish to lay eggs I usually have problems getting them to hatch, and if they hatch they seem to grow poorly.  I have tried many things that better breeders have suggested, but my record of success has always been poor.  Long-fiber sphagnum moss solved the rearing fry problem.  Once the eggs in my incubators hatched I would drop in some moss for them to hide under.  The fry would become free swimming after a few days and start to eat.  I am pretty sure that the micro-fauna on the moss was a part of their diet.  After a week or so the fry have their first color change, which is when I transferred them to a larger rearing tank (usually a 20 litre tank).  I was in a hurry one day and the only tank I could put the cory fry into had a layer of moss in the bottom and some 2-day old free-swimming danio fry.  I knew the fish would not bother each other, so I transferred about 20 C. duplicareus into the tank.  They grew much faster than in a bare tank, and with no losses.  I now use a 1” layer of moss in all my cory fry tanks.  I also use it for Ancistrus sp. (bristlenose plecos) fry.



I also use moss for raising cichlid fry.  If I am forced to remove very young fry from the parents, I transfer them to a small tank with a thin layer (less than 2.5cm) of moss on the bottom.  I think it does as much good for the cichlids as it does for the catfish.  If I am raising the fry in the tank with the parents, I like to place a couple piles of moss in different places around the tank.  The mother will lead her fry to these piles to forage.  I use a dropper pipette to put the fry food (baby brine, microworm or powdered flake foods) directly into the pile of moss where the fry are foraging.  This keeps the food in one place and provides a very natural way for the fish to forage.  Some cichlids parents will actually grab the moss and shake the food out of it in front of their fry.”



(Ted breeds South American cichlids, as well as cichlids fromGabon, so this may well apply to some African cichlids)

“I also use moss to stuff the nesting sites of most of my soft-water cave-spawning dwarf cichlids.  The moss does three beneficial things.  First, it provides a more confined and comfortable place for females to nest.  Most spawning sites in the wild are not clean of matter, nor are they large and open.  My  Parananochromis brevirostris and P. gabonicus like the moss packed in very tight — so much so that the female has to wriggle her way in.”

(Ted  observed in Gabon that the Parananochromis are strongly associated with muddy bottoms and leaf litter… deep leaf litter is some cases. One of the reasons they are not so easy to collect is that they may infact be ‘litter divers’ and bury themselves deep into the substrate to escape predation (aka… the nets). In one case, P. ornatus, to even catch a few they had to scoop up mud and leaves from slow sections of the stream and pick through it.)

“Second, the moss will decompose in the cave and create a microhabitat that is slightly more acidic than the water outside the cave.  This is very important for some hard-to-spawn black water species of Apistogramma, which lay eggs that are very susceptible to bacterial infection unless the water has an antiseptic acidity (less than pH 5).  It is hard to get the pH in and entire aquarium that low, but if you can get it close the moss in the cave will finish the job where it matters the most.

Third, the moss is a breeding ground for microorganisms.  Those wee beasties are food for fry in the cave.  If given the chance, fry will forage and feed all of the time.  That is one reason fish grow so much faster in the wild than in an aquarium.  Our tanks are relatively food-sterile compared to the wild, and the fish have to wait for us to feed them.  The more we can provide in the way of naturally reproducing foods in the aquarium itself the better.

Adding long-fiber sphagnum moss to your fish breeding tool kit will help you to be more successful.  I am sure that there are many other ways to use the moss than I know of.”

Well, there you have it. Perhaps you would like to try this method, or will come up with ideas and results of your very own!

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