July 10, 2018

The "nutrient trap?" Or just a place where fish forage?

Those of you who read my rants regularly know that I hate over-generalizations about stuff in the hobby.

And one of the most maligned topics in the world of aquarium husbandry is...detritus.

My never-ending war on behalf of detritus continues.

Yeah, you heard me...On BEHALF of detritus!

Seriously.

I know that uneaten food and fish poop, accumulating in a closed system can be problematic if overall husbandry issues are not attended to. I know that it can decompose, overwhelm the biological filtration capacity of the tank if left unchecked. And that can lead to a smelly, dirty-looking system with diminished water quality. I know that. You know that. In fact, pretty much everyone in the hobby knows that.

Yet, we've sort of heaped detritus into this "catch-all" descriptor which has an overall "bad" connotation to it. Like, anything which is allowed to break down in the tank and accumulate is bad.

The definition as accepted in the aquarium hobby is kind of sketchy in this regard; not flattering at the very least:

"detritus is dead particulate organic matter. It typically includes the bodies or fragments of dead organisms, as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose or remineralize the material." (Source: The Aquarium Wiki)

Everyone thinks that it is so bad.

I'm not buying it.

Why is this necessarily a "bad" thing?

I mean, even in the above the definition, there is the part about being "colonized by communities of microorganisms which act to decompose or remineralize..."

It's being processed. Utilized. What do these microorganisms do? They eat it...They render it inert. And in the process, they contribute to the biological diversity and arguably even the stability of the system. Some of them are utilized as food by other creatures. Important in a closed system, I should think.

It's not all bad, right?

In nature, the leaf litter "community" of fishes, insects, fungi, and microorganisms is really important to the overall tropical enviroment, as it assimilates terrestrial material into the blackwater aquatic system, and acts to reduce the loss of nutrients to the forest which would inevitably occur if all the material which fell into the streams was washed downstream!

Stuff is being used by life forms.

Okay, detritus as we see it may not be the most attractive thing to look at in our tanks. I'll give you that. It looks like a pile of sh---.

However, is it always a bad thing? What does it mean? Take into consideration botanicals.

If you're one of those hobbyists who allows your leaves and other botanicals to break down completely into the tank, what happens? Do you see a decline in water quality? A noticeable uptick in nitrate or other signs? Does anyone ever do water tests to confirm the "detritus is dangerous" theory, or do we simply rely on what "they" say in the books and forums?

Is there ever a situation, a place, or a circumstance where leaving the detritus "in play" is actually a benefit, as opposed to a problem?

I think so.

Now, I'm just one guy, but I personally haven't had issues with the complete decomposition of botanicals and leaves being left to accumulate in my aquariums. In almost two decades of playing with this stuff, and being a hardcore, water-quality-testing reef keeper during much of that time, I can't ever, EVER recall I time where the decline of a system I maintained could be pinned on the detritus as a causative factor in reducing water quality.

In fact, I have never had a situation where water quality has been an issue in a tank not performing well. And I suspect- neither have many of you.

Okay, put me in for a medal, right?

That's not the point.

What I'm getting at is that I have always been a firm believer in some forms of nutrient export being employed in every single tank I maintain. Typically, it's regular water exchanges. Not "when I think about it', or "periodically", mind you.

Nope, it's weekly.

Now I'm not saying that you can essentially disobey all the common sense husbandry practices we've come to know and love in the hobby (like not overcrowding/overfeeding, etc.) and just change the water weekly and everything's good.

What I am saying is that incorporating regular water exchanges into your system gives you the ability to dilute any potential accumulating organics/pollutants before they become a significant negative ve impact on water quality.

They simply give you a bit of a "buffer", essentially.

I don't need to go into the well-trodden reasons about what water exchanges are a good thing in the aquarium. However, I do need to give us a collective whack upside the head and encourage each and every one of us to think about this stuff from the perspective of an overall closed ecosystem. Think about what the nitrogen cycle is and does, and think about the impact of inputs and exports into and out of our closed systems.

Think about the potential benefits of allowing some of this stuff to remain.

Think about the organisms which feed upon it, their impact on the water quality, and on the organisms which fed on them. Then, think about the fishes and how they utilize not only the material itself, but the organisms which consume it.

Consider its role in the overall ecosystem...

Is detritus a nutrient trap?

Or is it a place for fishes to forage in? A place for larval fishes to seek refuge and sustenance in? Kind of like they do in nature, and have done so for eons. Yes, we're talking about a closed ecosystem here, which doesn't have all of the millions of minute inputs and exports and nuances that nature does, but structurally and functionally, we have some of them at the highest levels (ie; water going in and coming out, food sources being added, stuff being exported, etc.).

I think we really need to think about our systems- particularly in the blackwater/botanical-style aquarium world- as little microcosms which replicate- at least on some level, some of the process which occur in nature to create a specialized but highly productive and successful- not to mention, dynamic- ecology.

There is so much more to this stuff than buying in unflinchingly to generalized statements like "detritus is bad."

It's a mental shift.

A perspective of open-minded curiosity...and a willingness to look at things a bit differently and go beyond the usual and generally accepted ideas on stuff. It's not always pretty. It's not always right. I'll give you that much.