Mulm and Fry Tanks

[Cinnebuns]

Due to a recent post I made, I have been learning about mulm in my main tank. This sparked a thought about my fry tank. I usually clean it daily and occasionally have 2x a day. When I clean I try to get it pretty spotless assuming that sitting waste is harmful. My research into mulm makes me question this choice. How heavily should I be cleaning my fry tanks of waste and such?

The tanks are holding both guppy and panda cory fry. Eventually the 2 species will probably have seperaye grow out tanks. I assume this would effect the cories more than the guppies. 

 

Another considering factor is that almost all days I am able to get in 4-6 feedings. 

Edited April 2, 2022 by Cinnebuns

[ange]

I personally don't fret over particles in fry tank. It may affect the overall survival rate slightly, but the fish will be stronger for it. One of the problems that I see in breeding (not a hill to die on, just an observation) is that people whose livelihood relies on breeding have to make sacrifices in the name of producing the highest number of sellable fish. This includes things like pulling the parents, which makes it less likely for parental species to raise their own young successfully, but also includes keeping the water absolutely pristine. This is especially prevalent in fancy guppies as they tend to be raised in water with UV sterilizers and in some cases even brackish water.

One of my favorite anecdotes that I've retained from an ACO broadcast is that if you can get 2 generations of something in your water, they'll be bullet proof. I don't know if you're breeding for yourself or for local distribution, but I think it's worth considering the anecdote for both. We often forget that fish have high reproductive potential and that in wild conditions, very few will make it to reproductive age. Even going as far as protecting the babies from predation and ensuring that they have adequate food is far more than what most of these fish would receive in the wild.

This is my own judgement so feel free to take it with a grain of salt, but the mentality that fry must be kept in pristine water because they're sensitive has created a self-fulfilling prophecy. Fry who may have struggled in less than optimal conditions are making it because they've essentially been bubble wrapped, and there's not a clear way to tell how hardy the individual fry are until you introduce them to a less optimal condition.

My last anecdote will be German blue rams, as they're a hobby favorite and one of my own favorites as well. They were selectively bred in higher temperatures (because that's an inexpensive way to prevent parasites in some cases), which ultimately led to the near necessity to keep them in such high temperatures. The main evidence against this being the cause of this necessity is by observing the water temperatures in their native environments (rivers in Colombia and Venezuela), which range from 78-82F/26-28C. Sure it's lower than the hobby recommendation (84F/29C), but raising the temp is a common practice in the hobby when you're contending with microbes and other health risks.

If you like doing research, "genetic drift" is the main concept that I would advise reading into. It's the starting point that I used for my theory about why GBRs prefer hot water and why so many species in the hobby are considered "sensitive".

[Widgets]

In my shrimp tank where I had unexpected Zebra Danio fry, there is a huge amount of microfauna. It is my opinion that the mulm in the tank is feeding that microfauna, which then serves as food for the fry. I have a UGF and have not done any gravel vacuuming, just regular weekly 25% water changes. As long as the water parameters stay stable, I don't plan on changing anything. 

[Cinnebuns]

This point reminds me of why I intentionally leave the fry in the main tank for least half a day at first. Letting the weak die off strengthens the stronger genes that are passed on making each generation better. I think I might find a middle ground between cleaning and leaving it be. I'm still tempted to clean a tank with cory fry more since they are always on the bottom. 

[Streetwise]

I love mulm. My shrimp can survive on mulm, and snails too. I don’t vacuum anything.

[Guppysnail]

I make ugly tanks intentionally to hatch and raise fish. The uglier I get them the more micro fauna thrives. The more micro fauna thrives the more fry thrive. 30 CPD hatched and raised in this tank as well as 10 struggling bn pleco babies were placed here. Within 1 week the pleco babies turned the corner to thrive. 

Edited April 3, 2022 by Guppysnail