Seahorses, bacteria, & temperature

[KJHawley]

The recent issue of Advanced Aquarist (March 2011) had an interesting article about bacteria in saltwater aquariums (http://www.advancedaquarist.com/2011/3/aafeature.

It's not about seahorses, & relates more to protein skimming and GAC, but it got me wondering about the recommendation to keep seahorses in lower temperatures. I usually hear that seahorses need to be kept at lower temperatures because they are more prone to bacterial infections at higher temperatures. The reason stated for this is that aquarium water isn't as clean / has more bacteria than natural sea water, so the temperature is kept lower to help them fight off all the additional bacteria.

This article has almost the opposite conclusion. It states that aquarium water - when skimmed - actually has LESS bacteria than natural seawater. More natural, unskimmed aquariums tend to have about the same levels of bacteria as seawater.

I'm not suggesting that seahorses should therefore be kept under higher temperatures - I just wonder if there might be another reason why seahorses can fight off bacterial infections better in lower temperatures.

 

[rayjay]

Seahorse tanks normally have more problems with bacteria firstly because they seem to be much more prone to it than other fish, and secondly, because the seahorse tanks, due to their messy eating habits, provide more breeding grounds for growth of bacteria, especially as temperatures rise.
This bacteria can be growing on food left lying on the bottom or trapped between decor or rock structure, and is not removed by skimming
The best explanation I've read comes from Dan Underwood of seahorse source. com.
A COMMENTARY ON TEMPERATURE BY DAN UNDERWOOD

 

[KJHawley]

That is a very good article. I think it fits nicely with the other research about bacteria.

So, it seems like there are two ways to keep seahorses: 1) low temperatures and infrequent dead/frozen foods, and 2) high temperatures and frequent, live foods. It seems like a lot has been done to keep and rear seahorses under the first paradigm. Has anyone heard of someone who has been successful with the second - high temperatures and a constant source of live foods? It seems like, in the long run, that's the direction seahorse keeping out to go. As others have mentioned, seahorses are more active at higher temperatures, and it reflects their natural setting better. Also, if one could culture live foods (like mysis) in the aquarium with the seahorses, it would emulate their natural feeding style.

Here's an idea - take a relatively large tank (like, for example, 120 gallons), and separate it into 2 sections (saving 40-60 gallons for the seahorses), using glass, acrylic, eggcrate, or whatever. Culture live mysis (or other amphipods that thrive in the same temperature / salinity as seahorses) in the larger half, using big mats of Ulva or other macroalgae. Periodically - perhaps once a day - move one of the big Ulva mats into the seahorses' section. They can then spend hours hunting through the algae for nibblets. When the Ulva looks depleted - once a day, twice a day, whatever works - swap out the Ulva again.


They key, of course, would be figuring out how much area of live food growing algae is needed per seahorse. It might be far greater than what is feasible with this system. If it works, it would allow the seahorses to live in an environment that they're much more biologically suited to.

 

[DanU]

Yes there are some that keep seahorses using only live foods but they collect those foods. Primarily, those that I know live on or near the shore in the south. By higher temps I mean whatever ambient temps are, usually near 80 degrees.

The idea of the split tank I don't think will work. The primary diet of larger seahorses is shrimp and larger organisms. You could not grow enough in that small of a place. I recently got an order of shrimp, 500 PL 10's and fed them out to my brood stock, about 20 seahorses. All were gone within a couple of hours.

Regarding the skimmer, it certainly helps on a seahorse tank. I also think many folks make the mistake of not having enough flow in their tank which helps lift out some of the organics.

As for the activity. I don't notice any difference in activity levels when our temps drop to 69 to 70 degrees. In fact, the H. barbouri breed more at these temperatures. H. reidi, H. ingens, H. erectus, H. kuda and H. zosterae all seem to do equally as well.

Long term for the hobby of keeping seahorses we need to dispel some of the myths and teach folks the correct ways to set and feed seahorses. There are many that are keeping seahorses successfully long term in aquaria. It is not uncommon for us to get a call for replacing a seahorse that was lost after 5 to 10 years. They had to be doing something right, especially when you consider that many uneducated hobbyists don't get past a few months.

Still lots to learn!!!!!!!

Dan

 

[DanU]

The article in Advanced Aquarist was quiet interesting.

What I didn't learn from the article is whether or not pathogenic bacteria are removed from the water. Even if they aren't, removing nutrients is beneficial in a seahorse type tank. Too high of a nutrient level in the water leads to increased bacterial growth.

Some often describe seahorses as messy eaters or as having a high bioload. Seahorses when feeding macerate their food during intake. When this happens many describe the "blowing smoke out the back of their head" phenomenon. What is happening is that the food is macerated and some of the particles of the food are literally blown into the water column as undisolved organics. Consider also that seahorse digestive tract is rather rudimentary without a true stomach. What food enters is typically through the digestive tract in as few as 10 hours. Much of what comes out is undigested food particles. This too contributes to organic load in the water. I suspect there are different bacteria that come into play with proteins and fats than with just plain carbon dosing as with ETOH.

I have noticed that with the use of probiotics with seahorses that the amount of feces excreted is dramatically reduced. This is probably due to the bacteria adding in the digestion of the food leading to a better food conversion ratio.

BTW, the manufacturer of NP BioPellets recommends placing the out take of the filter near the skimmer to help remove bacteria from the water column. The BioPellets are designed for nitrifying and denitrifying bacteria.

Dan