Decompression Time

[greenmonkey51]

I was reading a thread and I thought of this. A lot of fish we keep are caught at deep depths. From what I've seen the typical procedure is to just slowly bring up the fish over a bunch of hours. Thinking back to my frontosa days and reading an article about collecting the Zaire variant, which is caught at depths of 30-40 meters. The standard procedure is to bring them up slowly over 3-5 days instead. Generally problems with swim bladders are reduced when following this. Is it possible that the fish are brought up too quickly. Especially when collectors pin the fish if there having trouble with decompression. Any thoughts

 

[leebca]

The following is mixed with information, facts, and my opinion.

Decompression is a real concern for fishes that are captured at depths below 25-40 meters. Fortunately, most of our common ornamental reef fishes have a rather great depth range such that, the ones captured and kept by hobbyists and aquarists are in shallow reef waters. Fishes deeper than this are not part of the trade and, if they are introduced into the trade, do not do very well.

For example, the Tear Drop Butterflyfish can be found at a variety of depths. The collector would not want to have to go deep to collect the fish since it causes problems (i.e., greater time and expense) for the collector/diver -- not just a decompression issue for the fish. Also, fishes that are living at such depths are not tolerant of much light. They don't make good aquarium additions where we like to bring out their colors with bright lights. So, in this case, the Tear Drop is collected in shallow waters. It is offered to aquarists at 'reasonable' prices.

Other fish, such as the Tinker's Butterflyfish are mostly found at greater depths. They are expensive because of the expense of having to go deep to collect them. They are not easy to find in the trade. A collector can collect one Tinker's or a few dozen other fishes in the same time at less expense, making more money for the others than the single Tinker's. Tinker's are NOT rare -- they are just less collected because of the collector's economical perspective.

The bottom line is, IF the fish did come from great depths, then the price of the fish should reflect this. If the fish is very inexpensive and yet supposedly came from a great depth, then it is likely the fish didn't come from that depth (even though the seller is making such claims).

Fish collected at great depths do require proper decompression and this adds to stress, more time spent without foods and nutrition, and results in the lesser likelihood of captive acclimation. Collectors run a business and the fish are commodities which, if they are dead, only serve as food. Thereby comes the recommendation, 'Leave deep sea fishes in the sea.'

 

[greenmonkey51]

I completely understand the depth vs price issue and thats one thing I like about keeping fish is that the price is reflected on how hard it is to get to market. I'm mainly talking about the deeper water fish that are only found at that range. So what your saying is that the collectors take a gamble on the fish recovering quicker from a bad decompression than stressing out during a long decompression.

 

[leebca]

Actually, the collector doesn't take much of the gamble. The fish moves through the system before it dies or what we just chalk up to 'didn't acclimate.' I'm not too sure that a postmortem could definitively find a decompression issue. I should think it would require a blood analysis. On this, though, I'm unsure. It's a good question for me to ask others.

The deep sea fishes should not be a part of our hobby. :evil:

 

[WPH]

The general rule of thumb when bringing up a fish at depth is 6 feet every 20 minutes....your decompression line will have knots tied every six feet. A typical dive day will include three dives.....starting with the deepest dive first.....Say a Tinkers is Caught at 160 feet.. The fish will be brought up at a maximum speed of 18 ft. per hour.....160 divided by 18 ft....It will take almost 9 hours to properly decompress a fish...ALoha Les

NEVER BUY A FISH THAT HAS A SWOLLEN STOMACH

NEVER BUY A FISH THAT SWIMS LIKE IT'S WADDLING.

NEVER BUY A FISH THAT SWIMS WITH ITS HEAD ALWAYS POINTING UP WHILE ITS BOBBING

NEVER BUY A FISH THATS SWIMMING WITH ITS HEAD CONSTANTLY IN A DOWNWARD MOTION

ANY FISH SHOWING THESE SYMPTOMS IS SUFFERING FROM DECOMPRESSION ILLNESS OR A BLADDER INFECTION FROM BEING PINNED WITH A HYPO NEEDLE AND DECOMPRESSED IMPROPERLY....

 

[csababubbles]

For example, the Tear Drop Butterflyfish can be found at a variety of depths. The collector would not want to have to go deep to collect the fish since it causes problems (i.e., greater time and expense) for the collector/diver -- not just a decompression issue for the fish. Also, fishes that are living at such depths are not tolerant of much light. They don't make good aquarium additions where we like to bring out their colors with bright lights. So, in this case, the Tear Drop is collected in shallow waters. It is offered to aquarists at 'reasonable' prices.
'

Shhhh!! I told my teardrop he was a deep-water rarity so don't go ruining it for him.