first livestock for 2,5gallon??

[Tavero]

Personally/my opinion

I would not add any fish to this aquriam, I thought mine was small at 40g 200litres.
I understand you have another aquriam set up so I assume you know about 'fish stress'
Maybe disregard this 2.5g as a setup for marine life and maybe build/create another?
Anything you add to this 2.5g will have a very short life expectancy.

Thing is, a 40g tank would be already too large for the animals i have mentioned earlier and they would actually have a shorter life expectancy there. Some animals are doing better in a species tank without faster tank mates. Other animals are bad for large tanks because you never see them.
I have seen my pompom crab five times in 2 years in my 15g tank.

 

[i cant think]

Thing is, a 40g tank would be already too large for the animals i have mentioned earlier and they would actually have a shorter life expectancy there. Some animals are doing better in a species tank without faster tank mates. Other animals are bad for large tanks because you never see them.
I have seen my pompom crab five times in 2 years in my 15g tank.

Do you have any aggressive fish in your 15g tank? I had a 20g where I saw my pom Pom constantly but I saw many of my other fish/inverts weekly if not daily. I had 10 fish total at one point in that tank and 6 of them were gobies with 1 blenny and then 3 wrasses. Here’s an FTS of that tank when it was I believe almost a year old, the algae wasn’t due to over stocking and actually just one more fish solved the algae issue. This FTS shows 4 of the 10 fish I once had in that tank (I still have most of those fish but some died of old age).

 

[Tavero]

Do you have any aggressive fish in your 15g tank? I had a 20g where I saw my pom Pom constantly but I saw many of my other fish/inverts weekly if not daily. I had 10 fish total at one point in that tank and 6 of them were gobies with 1 blenny and then 3 wrasses. Here’s an FTS of that tank when it was I believe almost a year old, the algae wasn’t due to over stocking and actually just one more fish solved the algae issue. This FTS shows 4 of the 10 fish I once had in that tank (I still have most of those fish but some died of old age).

I only had some goby okinawae and a small blenny. That thing disappeared into my rock scape and went missing for the next few months. Even after that i've only seen it a few times during night. I've read somewhere that they eat bristleworms so in that case you can't even bait them with food because they are always full anyway.

 

[Rick's Reviews]

for now there is a smal hermit crab who has it all for it self. maybe ill keep some sexy shrimp or other realy small inverts. corals are definitly goin in, witch i also see as marine life.i get that stress is a huge factor for fish and i wont go with anything to big and so i dont realy see why small inverts/fish would die faster in a smaller aquarium if al the paramaters are kept tightly and inhabitants fed well.

I agree if all parimiters are kept tight, it may be possible.

I'm just unsure of survivability due to lack of 'swimming room',. a tiny addition would not grow much/slower than in a bigger aquarium.
(Just my opinion)

 

[Aleksei King]

why not a Lotilia graciliosa. Another small goby but even in that I doubt youll see it everyday. Or a griessingei goby. Both would do absolutely fine in that tank for life space wise.