First reef tank, trying to build an ecosystem...

[Hannah_L]

Hi Everyone,

I'll post the progression of my tank from when it was set up in March 2025 until now, but first a little background.

I live in Mauritius and during school holidays, we'd fill an old tank at my grandparents house with sea water from the lagoon and spend a few weeks fishing in the rock pools and adding them to the aquarium. At the end of the holidays we'd put the fish back in the lagoon and the tank would go in the garage until next year. It was always great fun but we definitely made some interesting tank choices...like a lionfish.

Anyway, I now have my own place and have been toying with starting a proper reef tank. I had been inspired by a uncle who had a small tank he would experiment with and when he found interesting things in the lagoon, he'd add them to the tank...

So before I started with an impulse buy, I decided to do some research. In that, this forum was really helpful.

Given that this was a first try, I didn't want to go too expensive in case it didn't work out....so decided to stay local. Now I'm really lucky that I live on a tropical island with barrier reefs, the perfect ecosystem was on my doorstep.

I decided I wanted to recreate the lagoon in miniature to get as robust of an ecosystem system running in the tank. So with the research done it was time to get a tank....

 

[Hannah_L]

Hi Everyone,

I'll post the progression of my tank from when it was set up in March 2025 until now, but first a little background.

I live in Mauritius and during school holidays, we'd fill an old tank at my grandparents house with sea water from the lagoon and spend a few weeks fishing in the rock pools and adding them to the aquarium. At the end of the holidays we'd put the fish back in the lagoon and the tank would go in the garage until next year. It was always great fun but we definitely made some interesting tank choices...like a lionfish.

Anyway, I now have my own place and have been toying with starting a proper reef tank. I had been inspired by a uncle who had a small tank he would experiment with and when he found interesting things in the lagoon, he'd add them to the tank...

So before I started with an impulse buy, I decided to do some research. In that, this forum was really helpful.

Given that this was a first try, I didn't want to go too expensive in case it didn't work out....so decided to stay local. Now I'm really lucky that I live on a tropical island with barrier reefs, the perfect ecosystem was on my doorstep.

I decided I wanted to recreate the lagoon in miniature to get as robust of an ecosystem system running in the tank. So with the research done it was time to get a tank....

Hauled the old tank and Cabinet out of the garage... the glass of the tank had gone couldy with age and mineral deposits and I couldn't get it clear, however the cabinet was good to go after a thorough clean and a new coat of paint.

Got a fairly similar sized tank (30G /115lts) from a LFS (all fresh water ones) to fit the cabinet and it came with a hood (which I wanted), light (not rated for corals), thermometer and kind of a sponge filter.

So here's a picture of the set up.

I'm running an undergravel filter as well as I like how well they work and also how you don't need to fuss over them once set up.

This I where I got ahead of myself a bit....
I was now super excited to get stuff in the tank, so got some coarse sand (coral and Shell bits) from the beach and went and got a big old piece of rock (dead coral) covered in coralline algae, algae and all the good stuff to get my microbiome up and running....

Also added some corals as I couldn't help myself from picking up some smaller broken bits in the lagoon....I know, I know, way to early but I couldn't help myself.

 

[Tahoe61]

Lovely. Boy I have not seen an undergravel in years. I remember when they were state of the art.
Time spent beach combing and tide pooling is the best time in the world.

 

[brittlestar]

beautiful corals! I love seeing tanks that actually look like a reef

 

[Hannah_L]

Lovely. Boy I have not seen an undergravel in years. I remember when they were state of the art.
Time spent beach combing and tide pooling is the best time in the world.

I used to run a fresh water tank on an undergravel filter when I was a kid...under my dad's reccomendation and I like how easy they are to run and also the angle of trying to get a balanced ecosystem in the tank with the microbiome in the gravel and the rest of the tank.

Admittedly I had a shortcut to getting my ecosystem up and running as there is a fully functioning marine ecosystem practically on my doorstep.

 

[Hannah_L]

beautiful corals! I love seeing tanks that actually look like a reef

Thanks, I had fun trying to get it to look like a reef in miniature

 

[The_Bro]

Awesome slice of the ocean. So cool seeing a tank where every component is hand picked from a lagoon near your house.

 

[Hannah_L]

Hauled the old tank and Cabinet out of the garage... the glass of the tank had gone couldy with age and mineral deposits and I couldn't get it clear, however the cabinet was good to go after a thorough clean and a new coat of paint.

Got a fairly similar sized tank (30G /115lts) from a LFS (all fresh water ones) to fit the cabinet and it came with a hood (which I wanted), light (not rated for corals), thermometer and kind of a sponge filter.

So here's a picture of the set up.

I'm running an undergravel filter as well as I like how well they work and also how you don't need to fuss over them once set up.

This I where I got ahead of myself a bit....
I was now super excited to get stuff in the tank, so got some coarse sand (coral and Shell bits) from the beach and went and got a big old piece of rock (dead coral) covered in coralline algae, algae and all the good stuff to get my microbiome up and running....

Also added some corals as I couldn't help myself from picking up some smaller broken bits in the lagoon....I know, I know, way to early but I couldn't help myself.

Part 3 ;)

So after getting the tank running the fun started. This part was really cool as within days I had all sorts of creepy crawlies in the tank that must have come in on the rocks.

First hitchhikers:
A bunch of hermit crabs - seriously I found like a dozen small ones (<1cm) running around.
A few coral crabs and other crabs, some of these became problematic later...
Aiptasia - 2 tiny ones I thought were nice sea anemone to start...they disappeared by the end of the month, I think one of the tank residents got them.
2 pistol shrimp - these are seriously cool and some of my favourite residents now
1 unknown shrimp
A whole lot of tiny brittle stars about 2cm across that have since colonised the sand bed.
Assorted snails...still trying to ID some of them
Probably more stuff....

This was a really fun time to see what sort of wildlife had hitched a ride onto the tank from the rocks I picked up. Looking at them originally I would never have thought there were that many creatures living in the rock, but nature is amazing.

Unfortunately in the first few months a lost a few corals before my sister came back from Europe with a proper light for the tank. Shipping stuff to Mauritius can be a hassle and is quite expensive.
I took out the light the tank came with and installed the Fluval Reef light. Had wanted some thing that wasn't too expensive and had a low profile that would fit under the hood in the place of the old light.
Got to say I'm happy with the performance so far, but will see how it works in the long run with the salt creep.
My only issue with it, is the light doesn't switch itself back on after the power cuts out, you have to reconnect to it via the App to reset the clock and then it lights up. This is only a minor thing and only applies if you have power cuts.

Here's some pictures of my hitchhikers and clean up crew, including one of the problem crabs that keeps eating the clean up crew.

 

[Hannah_L]

Awesome slice of the ocean. So cool seeing a tank where every component is hand picked from a lagoon near your house.

Thanks, it's a lot of fun and makes me really look at what's in the ocean and I keep seeing things I've previously overlooked.

Have been only collecting loose/broken off fragments to try to minimise my impact.

It was a bit depressing last year as when I started the tank our lagoons hit 30 degrees (Celcius) and stayed there for 3 weeks. We lost a lot of corals and the softies just melted away. There's something hauntingly beautiful about these almost glowing white skeletons just after they've bleached.

Thankfully I'm starting to see signs of new corals establishing (they spawned around the island 3/4 months ago). So we should see recovery if we get a few years before the next big temp spike.

 

[Delightful Reefer]

I used under gravel filters when I was a kid, have not seen those in years. Did not even know they still made them. Thank you for sharing, brightened up my day!

 

[higher99]

You should do more inverts! Maybe a mantis shrimp

 

[Hannah_L]

Lovely. Boy I have not seen an undergravel in years. I remember when they were state of the art.
Time spent beach combing and tide pooling is the best time in the world.

Absolutely, I love fishing in the tide pools, got most of my CUC from there ;)

 

[Hannah_L]

You should do more inverts! Maybe a mantis shrimp

I'd love a mantis shrimp, but the species we get here are a bit large for my tank.
We get a lot of peacock mantis shrimp - gorgeous divas, I love them.

Might go night snorkelling to see what other shrimp I can catch...their eyes shine pink in the torchlight, making them easier to spot.

I've got a lovely collection of snails from the tide pools, most of which I'm trying to ID still, but will post some pics soon...

 

[higher99]

I'd love a mantis shrimp, but the species we get here are a bit large for my tank.
We get a lot of peacock mantis shrimp - gorgeous divas, I love them.

Might go night snorkelling to see what other shrimp I can catch...their eyes shine pink in the torchlight, making them easier to spot.

I've got a lovely collection of snails from the tide pools, most of which I'm trying to ID still, but will post some pics soon...

That'd be cool! I'm a huge invert person at heart, you should consider it!

 

[Hannah_L]

Part 4 :)

Now, 9 months in I seem to have managed to get thing more or less stable and can now see the corals being happy and extending their polyps, some of the softies have even grown...

So here's a list of the tank residents for now...
Fish - 2 juvenile White-tailed Dascyllus and 1 eye-bar goby (I think, gobies are hard to ID)
Crustaceans - 2 pistol shrimp, assorted coral crabs and hermit crabs, including 3 blue legged ones.
Shells - 7 money cowries, 1 snakehead cowrie, handful of black Nerita albicilla, 3 Conumurex decorus, other unidentified snails...
Clam! - Found a baby Tridacna maxima (10cm across) attached to a peice of coral rubble. He's my favourite :)
Stars - lots of tiny brittle stars, 1 red one - Fromia milleporella (only has 4 arms)

Corals: (most of them are small frags)
Softies - 3 clumps of Anthelia sp, 3 Sarcophyton sp, 2 different Capnella sp, 1 Sinularia sp....couldn't get much closer than genus on the softies
NEW! - Rhodactis rhodostoma (I thought it was a sea anemone)

Hard Corals - Millepora dichotoma (yes, I keep getting stung), Platygra sp, Pavona decussata (I think), Heliopora coerulea, Galaxea fasciculari

 

[higher99]

Part 4 :)

Now, 9 months in I seem to have managed to get thing more or less stable and can now see the corals being happy and extending their polyps, some of the softies have even grown...

So here's a list of the tank residents for now...
Fish - 2 juvenile White-tailed Dascyllus and 1 eye-bar goby (I think, gobies are hard to ID)
Crustaceans - 2 pistol shrimp, assorted coral crabs and hermit crabs, including 3 blue legged ones.
Shells - 7 money cowries, 1 snakehead cowrie, handful of black Nerita albicilla, 3 Conumurex decorus, other unidentified snails...
Clam! - Found a baby Tridacna maxima (10cm across) attached to a peice of coral rubble. He's my favourite :)
Stars - lots of tiny brittle stars, 1 red one - Fromia milleporella (only has 4 arms)

Corals: (most of them are small frags)
Softies - 3 clumps of Anthelia sp, 3 Sarcophyton sp, 2 different Capnella sp, 1 Sinularia sp....couldn't get much closer than genus on the softies
NEW! - Rhodactis rhodostoma (I thought it was a sea anemone)

Hard Corals - Millepora dichotoma (yes, I keep getting stung), Platygra sp, Pavona decussata (I think), Heliopora coerulea, Galaxea fasciculari

 

[higher99]

Love how everything looks so natural and non artificial. The rocks look the the ones from the reefs and not man-made.

Do you have any plans to add any macro algae in the future? I’d love to start a similar tank in the future, strictly for macro algae and tide pool creatures! I plan to get rocks from Tampa Bay Saltwater since they’re looks very natural and is actually grown in the sea. Keep us in the loop if you plan on getting any more inverts!

 

[Sharbuckles Reef]

This is going to be very cool. Looking forward to the progress. I’m always jealous of those who can walk to the ocean and see and collect such beautiful animals!

 

[Hannah_L]

Love how everything looks so natural and non artificial. The rocks look the the ones from the reefs and not man-made.

Do you have any plans to add any macro algae in the future? I’d love to start a similar tank in the future, strictly for macro algae and tide pool creatures! I plan to get rocks from Tampa Bay Saltwater since they’re looks very natural and is actually grown in the sea. Keep us in the loop if you plan on getting any more inverts!

I did try some macro algae, but between the fish, crabs, shrimps etc it didn't last the week :)