The Opae ula shrimp Forum and online store

8.29.2017: Late post of June/July 2016
Hi Everyone!
I'm new as a member to the site, but have been reading the posts since I started my Opae tank a little over a year ago.
Everyone's experiences, suggestions, and comments were so helpful in helping me to design my own Opae tank.

Even with all of the knowledge I gained from this site, my tank still had/has its share of problems.

Here's how it all started...
(Sorry, I didn't take too many photos of the first tank set-up. I'll do better from now on.)
I wanted a small tank, light on maintenance, and different from the "usual" tanks to put on my desk at work.

I bought a Fluval Spec III: 2.6 Gal from Amazon. I really liked the fact that it came with a 3-stage filter (biological, chemical, mechanical) since I wanted to reduce the amount of water changes and supplies I'd have to keep at work.
I had read that the Opae can get stuck in the filter section at the back of the tank, so I wedged pieces of sponge behind the openings to keep them in the main tank.

I bought white sand for the substrate, a large piece of "lava" rock from my LFS, a preserved fan coral and crown coral (not sure if that's what it really is called) from a local vendor (Coral Fish Hawaii), and 3 marimo moss balls (also from Amazon).

I used distilled water and marine ocean salt to mix the brackish water, testing the salinity with a refractometer to an SG of 1.009.

I set up the tank, and it was beautiful! IMHO...

Photo taken: June 8, 2016

I bought the Opae 'Ula from a local vendor and added them to the tank about a month later after the tank had had enough time to grow the beneficial bacterias necessary for the denitrification process (pH = 8.0, Ammonia = 0, Nitrite = 0, Nitrate = 10).

Photo taken: July 5, 2016

They are so fascinating to watch!
Then the trouble happened...

That tank does indeed look fabulous! Let us know what went wrong and we will get it all back on track for you :)

By the way welcome to the forum! Hope you enjoy your stay and ask away with any questions you want to get answered no matter how trivial you think they may be!


Sent from my iPhone using Tapatalk Pro

Thank you for your kind words Odin!
I'm so happy to have people to communicate with regarding Opae 'Ula.
At times, it felt very lonely trying to search for information on caring for Opae online.
I look forward to learning from others and sharing my experiences too.

Added in 38 minutes 44 seconds:
8.30.17: Late post of August to October 2016

I noticed that the output of the powerhead that came with the Fluval Spec III was too strong.
I remedied this by placing the pre-filter made for the Fluval Edge over the out put tube and lowering the flow rate to the lowest setting.

I also continued to research how to keep Opae and water parameters for brackish tanks, and I decided to upgrade the filter.
I removed the sponge that came with the Fluval Spec and replaced it with an "In-Tank" acrylic box which I stuffed with the existing biomax, SeaChem Purigen, and SeaChem Matrix.

Even though I had wedged sponge behind the slots between the main tank and the filter area, Opae were still getting into the filter section.
I had to check the filter section daily, turn off the powerhead, and carefully use the smallest net I've ever seen to wrangle the Opae and put them back in the main tank.
The In-Tank filter box made removing the filter components to do this daily check much easier!

I then started to see an accumulation of Opae poop (for lack of a better word) on the white sand substrate.
I guess since the water flow had been lowered, the surface of the sand was left undisturbed. It was quite unsightly!

Photo taken: October 3, 2016

I bought the smallest diameter gravel siphon I could find, tied a piece of netting over the opening, and tried to clean up the surface of the sand, but was so worried about sucking up an Opae and had such a difficult time navigating the siphon in such a small tank.
The 'crown coral' had also begun to turn brown (at the time, I didn't realize that this was the diatom stage to algae growth and thought that something was wrong).

I also began to read articles about how sand that is highly compacted (like mine was) can begin to form anaerobic conditions that when disturbed can release hydrogen sulfide gas bubbles that can be deadly to the inhabitants of the tank.

The new substrate information coupled with the daily checking for "escapees", the cleaning of the filter over the output tube and the unsightly sand and coral were turning this tank from my "low maintenance" dream to a daily battle.

Researching began again in earnest!

You don't need to run a filter at all. I have 2 tanks. One has a sponge filter & the other none at all. The tank without a filter is doing great. If I do feed I only use pure spirulina. I don't have to feed since there's lots of algae growing. I would ditch the filter. Keep in mind an Opae Ula tank is run completely opposite of a traditional tank. No feeding once established, no water changes, filtration, aeration. As much as we can't at times fathom this it is completely true.Think about the small one gallon jars that have rocks and opae in it that have been running for 10+ years. Keep it simple and enjoy.

I still think your tank looks amazing and I'm a real sucker for sand in a shrimp tank,like yourself i ran into the issue of shrimp poop sitting on the surface, ideally you don't want to keep disturbing the tank with maintenance so you may need to learn to live with the sight of it or change your substrate (i went through the same thing and changed my sand to crushed lava rock in my main tank). When you use crushed lava rock or crushed coral you will find the poop falls in the cracks of the substrate and 'disappears' out of sight never to be seen again. What are you feeding your shrimp may i ask?

Don't worry about pockets of gas building up too, you need really deep sand for this to be an issue on any dangerous scale.

Thank you Vorteil and Odin for your input and information! It's always great to learn from others' experiences. It's comforting to hear that others have run into the same issues as I have!

9.5.17: Late post of December 2016

There were so many changes to be made in an effort to create a comfortable habitat for my Opae.
The first change I made was to remove the "crown" coral and Marimo moss balls.
I also changed out the white sand for a coarser black sand.
I kept the black "lava" rock and added a java fern in the hopes that it would use up the nitrates in the tank.

Next, I looked for a filter that would be better suited for Opae.
Not having a filter isn't an option for me since I wanted to keep the water clean since it's in my office and people look at it often.
I came across undergravel, Hamburg Matten, and undergravel jet filters.

I decided against the undergravel filter since I didn't want the poop to accumulate under the gravel and need cleaning.
I decided to go with the Hamburg Matten and undergravel jet filters.

I had to modify the Spec III to achieve this.
I removed the stock dividing wall between the filter and main tank and reapplied silicone to ensure the tank was still water tight.
Then, I purchased a perforated plastic tank divider and used it to divide the filter area from the main tank.
I used the existing powerhead that came with the Spec III, but added pipes that ran from the filter section, through the tank divider and under the sand.
The powerhead pumps water from the filter area out to under the sand. I encased the powerhead in coarse foam to act as a pre-filter.

Behind the tank divider, I placed 2 sheets of polishing filter to catch larger debris, then ran an air line into the bottom of the tubing that ran from the filter area to the main tank.

I kept the Purigen, Matrix and Biomax and added Denitrate.
I don't have a picture of the new filter set up, but in my videos, you can see the tank divider and polishing filter sheets.

The HMF solved the problem of the Opae getting in to the filter area.
The HMF also agitates the surface of the water which stopped the problem of oil on the surface.
The coarse black sand makes the tank more aesthetically pleasing since I can't see the poop.

The water in crystal clear, but there's no algae growth.
I also realized that the "lava" rock has no crevices or hiding spots, and isn't real "lava" since it doesn't absorb water the way real lava does.
This leaves no place for the Opae to hide or the the anaerobic bacteria to breakdown nitrates.

The Opae are very active all the time, swimming, eating, and "surfing".
Visit my YouTube Channel for videos of my Opae
https://www.youtube.com/playlist?list=P ... OQ4aABtoAE

I feed my Opae 100% pure Spirulina...they go crazy for this stuff! It's like candy to them!