Hello world!!

Nice! They are fantastic grazers and they look awesome. Good pick.

Already bonded and not even in the tank yet.

Small update nano is going strong.halloween hermit,pistol shrimp and goby all still alive and well lol. Been doing 10-20% water changes every 7 days :) things seem to be happy!! :mrgreen:

Halloween hermit crab moulted :)

When using hang on back filter how often do you change the replaceable filter? the one with carbon stuff in it? I know not to touch the bio filter.

The carbon has a very limited effective lifespan. After a week it does very little but still works to some degree for another couple of weeks. I would personally change the filter every 3-4 weeks but rinse it out with each water change. If I understand you correctly you are using the type of filter pad that has the carbon and filter pad as a single disposable unit. If you have one with a sponge and carbon separate then just replace the carbon and rinse out the sponge as the sponge will last a very long time.

Thank you!! :)

spike-fin goby is the best goby for a "stablished" nano IMO

Look into clown gobies and neon gobies too.
Small tanks get tons of algae so might want to get an spiny star Astraea to clean the glass.
If u have good lights than a rock flower Anenome may do well too.