Removing eggs from rectangular pleco cave

Thankfully most of the L number catfish exhibit wonderful parental care and are for the most part able to be spawned in a home aquarium in a purpose made pleco breeding cave or even an improvised shelter. Most spawning events include a pleco breeding cave defended by the male, courtship with a female who deposits her eggs in the aquarium breeding cave in one or several sessions and then leaves the male to look after the eggs and take care of all parental duties.

Fortunately many of the most popular L number catfish species make wonderful fathers who care for their eggs and alevin (embryo with a head and tail stage) up until the fry have utilised their yolk sac reserves and are ready to start finding their first bites to eat.

L002 Alevin
L333 eggs in dish

For the majority of L number hobbyists who begin with the humble bristlenose catfish, there is very little need to intervene and remove eggs or fry from the male’s care as their species’ robustness means even with challenges the majority of plecostomus fry survive. However, the variable ability of bristlenose catfish males across species and even within a single colony can often lead to unending disappoint due to the endless number of ways individual or entire fry cohorts can be lost.
For example, the bristlenose male may eat the eggs after being stressed, a second bristlenose female may want to lay her eggs in the cave and eat or damage the current eggs or juveniles to give her own offspring a better chance, snails may get under the bristlenose male to eat eggs and even simple bad luck from a unfertilised egg going bad can ruin an entire clutch.

Over time in our experience, as pleco hobbyists grow in confidence and with the continued innovation of egg tumblers and fry boxes sustained success is greatly correlated to one’s ability to safely remove eggs approximately 36-48hrs after they are laid in the pleco breeding cave.


These 5 tips will help you become more comfortable with the egg collection process.


The most important benefit for removing eggs is the ability to intervene and remove unfertilised eggs that become sites for bacteria and fungus to colonise and eventually spread from one egg to another.
Male bristlenose catfish don’t have the dexterity of a human with a scalpel and have only their mouth to both grip and remove eggs which have developed fungal infections. This process is made even more difficult by their eyes being positioned on the top of their head. Often this results in the male eating eggs seemingly at random until the problem is removed even at the cost of good eggs.
As the stakes rise with individual fry worth significant monetary values it becomes a natural progression for a hobbyist to learn the skillsets to intervene and save at least 20% or even up to half of their spawns should the females produce clutches either too separated or too large for the male to fertilise properly.


From the many observations of skilled hobbyists, forum threads and the definitive Facebook Group Post the current accepted initiator of spawning events is in fact the male and not the female. The female may choose not to acknowledge the male, but if your male has no interest in spawning, there is simply nothing you can do apart from hoping another male is willing. During the courtship (trapping or egg laying period) to when the fry leave the cave for their first feed the male doesn’t eat which takes a tremendous toll on the male’s body.

For the past 10 years we have removed eggs from our male’s care approximately 36-48hrs after recording their arrival in the male’s fish breeding cave for every species apart from the standard bristlenose due to the minimal economic benefit. By removing the eggs after approximately 2 days instead of waiting until the approximate 14–20 day period the male’s metabolic energy reserves are vastly improved allowing him to be available for more “sessions” with more females.

*Consideration must be given to one’s method on egg collection and its impact on the male. This is something everybody will do differently so practice makes perfect.


L-number fry like all fish fry are at their most vulnerable when their body finishes the absorption of the egg yolk and begin the process of utilising their own food source’s energy which as you may guess is still very inefficient. L-number catfish species that have particularly small eggs such as longfin Lemon Blue Eye bristlenose require particular attention during their first three days of feeding to avoid significant fry mortality.

While it may be possible to enjoy good fry survival rates with a single pair of breeding plecostomus, when we had 120 adults for particular line breeding projects, it become vital to ensure as many individuals survived as feasible.

Another frequently overlooked consideration is that bristlenose fry will experience their alevin stages differently absorbing their yolk sacs at vastly different rates. This can lead to stunted growth or initial death when the male holds the individuals who use their reserves first back with the majority. By removing eggs individuals who develop faster, slower or perfectly on time can be looked after.


If you can think it, chances are eventually it will happen to cause issues with egg cohorts. Over the past two decades we have experienced snail invasions, male invasions, female invasions, planaria invasions, worm invasions, food invasions, poop invasions, plant invasions and most annoyingly older cohort invasions. Just to clarify by invasions we mean insanely unlikely events occurring leading to total disasters much like Murphy’s Law.

The more variables you can control with egg tumblers the easier the pleco hobby becomes.


For many species of L number catfish with particularly large eggs controlled hatching conditions from the egg are critical to ensure the delicate vertebrae of the spine aren’t damaged from the male not adjusting his fanning rates. Admittedly this is a particularly rare occurrence, but over the years we have had several males whose profuse fanning caused significant numbers of their fry to have bent spines. This occurrence is often attributed to inbreeding deformities and is a knowledge nugget for when significant numbers of fry from cohorts have spinal issues. This may or may not solve the issue as this was knowledge we were given as a suggestion which turned out to be the most unlikely solution.