Increasing stocking levels of mature tanks

[KenH]

In regards to fish stocking levels, I think that everyone agrees that it is always safer and wiser to understock tanks, especially new ones. The primary benefit is to help prevent the problems a high bioload can contribute to, such as rising nitrate levels or growth of hair algae, especially in newer setups.

This level of stocking is usually all that you see repeated on this and other boards since almost all responses are toned down to the beginner tank level since most questions are asked by, or assumed to be asked by, people new to the hobby.

On the other hand, it has been my observation that as the tank matures and if the stocking level of corals and clams goes up to more dense levels, there seems to be a synergy/dynamic affect in which a higher stocking level of fish seems to actually benefit the corals and tank in general. I believe that the higher stocking level puts more energy into the system in general and tends to benefit everyone.

Without starting a flame-fest and with the disclaiming that newbies shouldn't try this at home on their new setups, I would be interested in other peoples observations of mature, heavily stocked (fish and coral) tanks.

--- Ken

 

[Tanu]

KenH, you're right! I've noticed this synergistic effect between nitrates and coral growth in reefs years ago.
I wrote an article for 'Het Zee-aquarium', the Dutch/Belgian magazine for marine-enthousiasts.
In this article I compared the situation in our tanks with rainforests and greenhouses. While organisms in a rainforest (which is very nutrient-poor, just like the reefs in the ocean) have to fight for each little bit of nutrient, the same organism has enough delivery of the same nutrients in a greenhouse. With the controlled addition of more Carbon and nutrients, the same species grows much faster.

For myself I've done experiments with raised nitrate-levels in my reef. I raised the levels by feeding more or less. I am aware that by feeding more more than only nitrates are added, but I used the nitrate-level as some kind of indication. I raised the levels till 80 mg/l (yep, you read that right) in a sps dominated reef! I also kept some herbivores to keep algae in control.

Strange thing is that the algae didn't grow faster than with, say, 5 mg/l. For myself I like a little more nitrates than in nature, say, 10 mg/l. 80 mg/l didn't cause any problems, but newly added specimens seemed to have problems to adapt to these situations.

Now, I have a 50 G reef, mainly sps, I rarely do water changes. I have a oversized skimmer (I've seen these skimmers on 400 G tanks, didn't look undersized!), sometimes use ozone, each 3 months some carbon and so on..

For fish:
1 flame angel
1 yellow tang
5 Apogon leptacanthus
2 Amphiprion ocellaris
1 blue mandarin
1 6-line wrasse
1 lawnmower blenny
1 firefish
1 niger trigger. The niger is a guest from the lfs, he has to recover some damage and he has to grow a little more. For now, he is a perfect reef-citizen in my reef.
This pic is 1 day old, you can see for yourself my reef looks healty!

I've tested the water some weeks ago:
phosphate: zero, nitrate: zero (I wonder where the nitrate goes.. I feed very much!), pH: 8,3, alkalinity: 7, calcium: 450, salinity 1.023.
I still want to raise the nitrate-level a little, so I'm feeding even more as I first did.. The fish like it ;-)

Tanu www.tanu.nl

 

[KenH]

Hi Tanu,
Your tank was one of the ones I had in mind when I wrote this, along with a couple of local ones I am aware of. As people evolve in the hobby, this seems like a natural path to follow to maximize the appeal of the tank.

Over time, I think most people go through the same basic phases of measuring success with their tanks:

Phase 1: Putting polyps in the tank without having them go belly up.

Phase 2: Putting a relatively varied LPS and soft coral selection in the tank without major incident.

Phase 3: Migrating to more demanding SPS corals and clams in the tank. Start measuring success by how many watts you have over the tank and how deep your sandbed is

.

Phase 4: Maximizing the aquascaping and visual appeal of the display. I think it is this phase that many people are just now starting to reach. Certainly, your tank is considered one of the best aquascaped tanks around and has one of the higher bioloads as well, with a small to medium fish per 4 gallons or so. It is that natural 'slice of ocean' effect that most tanks are missing.

While most people spend a good deal of their time ensuring that none of their corals can interact, the most impressive tanks I have observed have significant, natural interaction occurring which adds considerably to the interest of the display. With this increased dynamic, some of your other thoughts I have seen you put forth, such as encouraging natural predation of some of the corals by fish, can come into play and add yet another dimension to the hobby. I suppose you may yet test that hypothesis with the niger trigger

.

My tanks have always had zero nitrates. I have always considered that a good thing. It does seem to make sense though, that if feeding is increased to the point that nitrates start to become measurable, you are at a point of feeding saturation that supports maximum energy in the tank. Increasing feeding past this level starts to sound a little risky, but I am willing to keep an open mind.

Can you give a feel for how much you are feeding on a daily basis at this time?

--- Ken

 

[DKKA]

Hi guys, I agree with you that increased stocking on mature tanks adds more energy to the system and benefits the corals and critters.
But the problem is that mature tanks also usually have mature fish. ie: territorial fish. I don't believe overstocking has anything to do anymore with nitrate/algae problems. Our filtration has advanced to the point that those don't need to be our major concerns. But aggression is still a problem. I'd wager that agressions kills WAY more fish than poor water quality.
Tanu - I'd love to have your stocking level in my 55, but my 10 year old clown, and my yellow tang won't allow for any newcomers.
Dan