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jnc324
07/21/2017, 12:47 AM
I was wondering how do importers get away with overstocking their tanks?

In New Zealand we have to quarantine all marine fish for a period of three weeks before they can be on-sold to the public.

I was wondering how do importers get away with large amounts of fish in small tanks?

I mean could you place 15/20 Yellow Tangs of 1" in a 10Gal for three weeks without a issue?

Sa6hir
07/21/2017, 02:55 AM
If they are doing it then they must be meeting the requirements. Obviously the fish ain't happy but if by "LAW" says that is the minimum requirement then they will do it. They will have excellent filtration otherwise all stock will be lost.


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jnc324
07/21/2017, 07:29 AM
There is no law on stocking tanks. However there is a huge cost of importing fish into the country. They need to go into a facility approved by the government and be checked by vets before they can be released.

To offset the cost importers will try and bring in as many fish as possible.

What I am trying to figure out is if they had a 600 Liter system made up of tanks being 60cm x 40cm x 40cm

what would be the maximum stocking you can place in these systems with say a skimmer rated 1200 liters?

Also how do they get there tanks ready for such a Bio load to hit all at once?

mcgyvr
07/21/2017, 08:03 AM
What do you think your acceptable mortality rate is vs theirs? ;)

karimwassef
07/21/2017, 10:47 AM
I'm not sure what the issue is... if it's just fish in subdued lighting, they just need a bacterial and mechanical filter to handle the waste. A pool sand filter will work just fine and if you have a problem, use big UV to zap it.

You just need to manual labor to backwash the sand filter regularly.

jnc324
07/21/2017, 09:25 PM
ive got no issue with it.

I am trying to figure out how they do it as I want to build a facility myself over the next 6-8 months to import my own fish.

karimwassef
07/21/2017, 09:55 PM
big sand filters and UV.

jnc324
07/21/2017, 10:20 PM
ah right.
So protein skimmers are a bonus to the water.
Basically my idea is heavily stocked tanks with good filtration so I dont need to do a water change for three weeks. That is an ideal plan.
Does anyone have a link to good quality sand filters?

karimwassef
07/22/2017, 02:46 AM
I don't expect importers feed much and the fish have usually evacuated before they get into containment. So I expect new waste is usually limited to ammonia which the sand filter can process. Protein skimming doesn't help unless there's a lot of particulate organics (or maybe dead fish being eaten up by the rest?).

Also, most keep salinity low to avoid parasites or diseases. The tanks may also be medicated.

jnc324
07/22/2017, 03:12 AM
was thinking about doing 600 liter systems that all fed into one large bed filter/skimmer and before it gets there it is zapped by a UV filter.

So systems - UV filter - Sump (bed filter/skimmer) - Return to systems.

would this isolate that issue to disease transfer?

djbon
07/22/2017, 05:17 AM
I have been to a huge LFS and they do have huge UV filter. The section where the bulb was in is literally lighted up by the UV bulb. There is a warning sign on it as well.

karimwassef
07/22/2017, 09:25 AM
What's a bed filter?

jnc324
07/22/2017, 10:21 PM
sand filter.

slief
07/30/2017, 08:48 AM
I live in Los Angeles and we have a number of importers here. Reducing initial losses/casualties is a big part of their philosophy when it comes to their system design and techniques. Most of the importers I've been to have massive systems with very large filtration systems including sand bed filters, large protein skimmers, UV, huge pumps with very high flow rates through their systems and last but not least, they do very large daily water changes. They generally have seperate systems for fish and inverts. The fish systems are typically run at low salinity levels around .014 to reduce stress on the fish, reduce the spread of parasites and reduce costs due to the volume and frequency of the water changes. This unfortunately can increase the casualty rate once the fish leave the wholesalers as many stores don't practice proper acclimatation techniques and go from really low salinity levels to more moderate levels too quickly. They don't match the salinity of the incoming water like they should and fish often suffer from osmotic shock and die within weeks as a result. Some wholesalers/importers use mixed salt while others use natural ocean water which they further dilute with fresh purified water to keep salinity levels down.


That said, a truly heavily stocked system would typically be around 1/2" of fish per gallon of water volume. Because of the life support equipment in those systems and the volume of water changes which can be as much as 50% a week, those rules get bent. In a typical display tank, 1/2" of fish per gallon of display volume is typically accepted in the industry as a heavy load.