Time: Feed > Metabolize > Waste

[Trouser Bark]

Do you want to actively remove the feces or is the main goal to reduce nitrates and possibly their precursors?

They're connected in my mind but I definitely see what you mean and hadn't broken it down in my thoughts that way before. I have a system running full time for solids so if I had to grade the two on a scale of which is more important to my goal it would be that NH3 > NO2 > NO3 > WC cycle.

 

[Trouser Bark]

I realize some here might get bored because I sometimes go on "ad nausium" about the importance of planted sump/refugiums as the major factor in efficient filtration, but I give 2 sh**s about turds, that in the end, feed my sumps overabundance of plants.

Don't stop. I've rethought aspects of my fish keeping in part due to several comments you've made. Your perspective is appreciated!

 

[esoxlucius]

Another thing worth noting here, and I find it comes in quite handy actually.

During a water change whilst I'm vacuuming bits of crud off the bottom, I notice that as the water level decreases the fish seem to poop for fun, which is great because I can vacuum it out as it's being produced!

I put this down to the change in water pressure having an effect on their gut, and the fact that my tank is the best part of 3ft deep!!

Has anybody else noticed this phenomenon?

 

[jjohnwm]

Although I have been a vacuumer for aesthetic reasons in the past, these days I seldom bother with turds...

I still chase 'em. I know that my water change routine is more than capable of dealing with any accumulating nitrates or other nasties in my water, so it's more of an OCD thing with me.

I won't pinch off a loaf in the corner of my living room...I wouldn't accept that behaviour from my dog either...and so even though I understand in an academic sense that it isn't strictly necessary for me to siphon or scoop aquarium turds, I just do it because it "feels" better not to see them laying around. And it's an ongoing battle, as most fish turds break down into powdery schmutz pretty quickly. Personally, I just like using a magnum-sized turkey baster to slurp them up as soon as I see them. And I'm not talking about the little microturds produced by small fish, which is mostly what I keep; I am referring strictly to the bloated-slug creations of my Jelly Cat (my only "big" fish) and my Axolotl.

Nobody sees my tanks but me... they aren't pretty, mostly just unfinished plywood on the outside...far from "display" tanks...but I want to enjoy looking at them, or at least what's inside them.

Of course, I also go out and shovel up my dog's turds almost immediately, so....yeah, nuts...

...During a water change whilst I'm vacuuming bits of crud off the bottom, I notice that as the water level decreases the fish seem to poop for fun, which is great because I can vacuum it out as it's being produced!

I put this down to the change in water pressure having an effect on their gut, and the fact that my tank is the best part of 3ft deep!!

Has anybody else noticed this phenomenon?

Yeah, Esox...you need to get out more...

 

[Flaring Afro]

Another thing worth noting here, and I find it comes in quite handy actually.

During a water change whilst I'm vacuuming bits of crud off the bottom, I notice that as the water level decreases the fish seem to poop for fun, which is great because I can vacuum it out as it's being produced!

I put this down to the change in water pressure having an effect on their gut, and the fact that my tank is the best part of 3ft deep!!

Has anybody else noticed this phenomenon?

I would think this is due to stress and not the water pressure.

 

[RD.]

Also interesting data; it makes me wonder if there are any fish whose intestines can vary in length at different times of year, similar to those of some bird species, to allow them to better utilize seasonal food supplies.

I had some time this morning to dig up a couple of old posts of mine regarding gastrointestinal plasticity.

I also wanted to revisit a previous comment. In the terrestrial vs aquatic plant matter discussion I posted the following, a quote from the study that the German group performed on Tanganyika, regarding gastrointestinal plasticity. It's not something just seen in various species of cichlids, or even fish, but also seen in reptiles, birds, and rodents.

"Second, intestinal plasticity has been demonstrated experimentally in perch (Olsson et al. 2007), prickleback fish (German et al. 2006) and Tropheus (P. McIntyre and Y. Vadeboncoeur, unpublished data), and observations in Lake Malawi cichlids suggest shortening of the gut in mouthbrooding females that are unable to feed regularly (Reinthal 1989). More generally, plasticity in internal organs in response to environmental stimuli has been documented in many vertebrates (reviewed in Piersma & Lindstrom 1997; Starck 1999), including fasting snakes (Starck & Beese 2002), migrating birds (Karasov et al. 2004) and rodents in fluctuating environments (Naya, Bozinovic & Karasov 2008), and the physiological mechanisms underlying gastrointestinal plasticity are well understood in several taxa (Starck 2003). Thus, we believe that the observed variation in T. brichardi intestine length is a largely plastic response to differences in the nutrient content of their algal diet."


I understand that in nature many complicated and often misunderstood processes take place, and that we are always left somewhat guessing at a lot of how this will all play out in a glass box, IME, many of the species that were once considered specialized feeders (in nature) that required specialized diets (in captivity) has not played out to be true.

I posted the following 2009 study in another sticky on bloat that I wrote several years ago, which demonstrates just how great intestinal plasticity can be in response to the diet quality of various species of cichlids found in Lake Tanganyika. Dietary adaptation at it's best, and again, even within different populations of the same species, within the same body of water.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2009.01589.x/full

Summary

1.  Among vertebrates, herbivores have longer digestive tracts than animals at higher trophic levels, a pattern thought to reflect a trade-off between digestive efficiency and tissue maintenance costs. However, phylogenetic influences on this pattern have rarely been considered. Taxa that have undergone diversification accompanied by dietary shifts provide a powerful opportunity to examine the relationship between diet and intestine length while accounting for phylogeny.

2.  In this paper we assess the relationship between diet and intestine length in the cichlid fishes of Lake Tanganyika, which are renowned for their diversity of species and trophic strategies.

3.  First, we test the effect of trophic position on intestine length across 32 species, while controlling for phylogeny. Trophic position was inferred from nitrogen stable isotopes, which provide a temporally integrated, quantitative perspective on the complex diets of tropical fish. Second, we examine patterns of intraspecific variation in intestine length of an algivorous cichlid (Tropheus brichardi) along a natural spatial gradient in algal nitrogen content.

4.  Trophic position explains 51% of size-standardized variation in intestine length after accounting for phylogeny. Accounting for phylogeny does not substantially alter the relationship between trophic position and intestine length, despite the existence of phylogenetic signal in both traits. Thus, diet is a strong predictor of variation at the interspecific level.

5.  There is a striking inverse relationship between intestine length and algal nutrient content among populations of T. brichardi, suggesting substantial plasticity in response to food quality, and thus a strong dietary influence on patterns of intraspecific variation.

6.  Diet is a strong predictor of intestine length at both intra- and interspecific scales, indicating that fish adjust their phenotype to balance nutritional needs against energetic costs. Furthermore, functional explanations for trophic diversification of cichlid fishes in the African Great Lakes have long focused on jaw structures, but our results indicate that intestinal plasticity in response to diet quality may also be an important mechanism for accommodating trophic shifts during evolutionary radiations.

 

[jjohnwm]

Wow...there's a lot of amazing info in those references, much of it well beyond my ability to comprehend. The concept of "tissue maintenance costs" was completely alien to me, but it seems to make much of this more logical and understandable.

When they discuss the "plasticity" of intestinal tracts and how it relates to the diversification of species, it sounds so obvious that one wonders why it needs to be discussed. But then they get down to how this plasticity occurs within a given population over a period of months as a response to food quality, and it becomes less obvious, although just as logical. And when it comes down to a change occurring within the females of a mouth-brooding fish species, due to the inability for those females to feed regularly...it is mind-blowing, to me at least. Perhaps other folks have more blow-resistant minds...

Thanks for posting that, RD. Very interesting stuff, certainly not "light reading" by any means.

I'm trying not to picture Trouser Bark performing his corn experiment...but I can practically hear his intestines getting longer from here...

 

[Trouser Bark]

Thanks for posting that, RD. Very interesting stuff, certainly not "light reading" by any means.

Yep. Very. A bunch of it was beyond my scope but interesting for certain.



I'm trying not to picture Trouser Bark performing his corn experiment...but I can practically hear his intestines getting longer from here...
[/QUOTE]


A green apple quick step day for sure. I believe I could whistle dixie through these pipes now. Let's try it, shall we? Key of C. Ready...

 

[jjohnwm]

Okay...this thread has gotten me thinking. After the initial cloud of smoke and dust, it occurred to me that timing big meals with water changes was likely futile...BUT...perhaps there are other ways to utilize the idea.

I always have a couple of sponge filters bubbling merrily away in my biggest sump, and sometimes in other places on occasions when an impending need for a new tank set-up is becoming apparent. Then, when setting up the new tank, I will fill it with 100% fresh new water at the correct temperature/chemistry, no skanky old aquarium water required or desired, and then plop one of those sponges in and immediately add fish. It's a common method used by many aquarists to avoid the time taken to cycle a tank from scratch, and it's much easier on the fish than a partially-cycled tank or, worse yet, a fish-in cycle. The method works; it has been literally years since I bothered to even test the water in a new tank started this way, and I have never had a problem with any of them.

Now, here's the thing: by doing it this way, I am taking advantage of the large area of biomedia that my sumps contain, and removing a certain percentage of it which of course brings with it a certain percentage of the bacterial colony. And when I do that, I tend to skip feeding in both the "donor" tank and the new one for a day or two. I have always assumed that the production of ammonia would slow down with minimal or no feeding, and speed up with heavy feeding. By not feeding for a day or two, I give the suddenly-reduced bacterial colony in the donor tank a chance to recover and reproduce up to near its original level, thus avoiding an ammonia spike. And in the new tank...depending upon how many fish I am stocking it with from the get-go...I am giving the small inoculation of bacteria time to build towards the numbers required to handle the bioload. If I foresee a heavy bioload in the new tank, I will go so far as to start it with two or even three sponges, harvested from different donor systems. This is just a minor hit at each of those established bacterial colonies, but starts the new tank off with a much more robust colony, perhaps already large enough for the purpose required of it.

Soooo...maybe I should think about a couple days of extra heavy feeding in the donor tank before "harvesting" the sponge? If that temporarily boosts the bacterial population...big "if", I know...then I would be getting more for my money when I transfer the sponge, starting off the new tank better than ever and causing even less in the donor tank. Win/Win.

Ain't it great? Thinking hard, while still producing nothing of real value and keeping myself entertained at the same time. Retirement is wonderful.

 

[esoxlucius]

And you think I need to get out more? Lol.