Aquarium Capaicy - Advice

[adrianborg]

Good morning!

I have a 240litre (63 gallon) aquarium. Currently it's home to 9 danios (zebra & leopard), 6 harlequin rasboras, 5 bristlenose catfish (babies, but I know they'll grow) and 4 clown loaches that are still quite small (about 2 inches or so).

I want to add some colour later on - I was thinking a pair of dwarf gouramis (blue) and a shoal of neon tetras - say 10-12.

Would this be stretching the capacity too far? The aquarium is well planted and has a good external filter pump (Fluval 305).

Thanks for your help,
Adrian

 

[Cossie1111]

This could possibly be stretching it, but you have to wait for someone more experienced than me for a definate answer.

However I do know that you should put in 3 gouramis, or 1 (not two) at a ratio of 1 male to 2 females to ensure no bullying.

I also know that clown loaches can get very big, and with 4, you could be looking at some problems down the track.

 

[Wills]

With 5 BNs it is kind of a heavy load when they get to adults, plecs produce a lot of waste and I would consider thinning the group out as they grow so you get maybe 1 male 1 female and see how it goes. Also the Clown Loaches are going to outgrow the tank though it will take a long long time... But you could consider swapping them now for something like Zebra Loaches or Dwarf Chain Loaches though this tank could handle larger ones like Yoyos.

I think if you did the above adding a shoal of Tetras and as Cossie1111 said a trio of Dwarf Gourami would be good 1m2f - though you could consider a larger species of Gourami like Pearls.

Wills

 

[N0body Of The Goat]

I think you need to look at your current stock, remove inappropriate ones that do not match up with which species you want to keep and then go from there...

• The (good sized group of) Leopard and Zebra Danios will love the 240l for life, presuming this is a 4-foot tank with lots of upper water current. However, they are temperate water fish, that do far better at 18-20C for most of the year with a "summer season" approaching 24C for a few months.
• The Clown Loaches will need at least 25C; lots of water current; need a bigger group to form a complex hierachy ("VickiandKev" had 30+ in a 8x4x4); will need a much bigger tank long term; prone to ich if the water quality is not good enough.
• The Harlequin Rasboras will be happy in a 240l for life, but they are not fans of strong water current. Their minimum temperature needs are slightly higher (21C) than the danios too, so not a good choice to mix.
• The 5 BN catfish will love water current, but need a minimum temperature of 21C. As "Wills" said, as these grow up they will produce an awful lot of waste, I recently visited a breeder where 20-odd ~2cm fry were demolishing half a 3" courgette in under 24 hours. Could potentially be problems long term if more than a couple turn out to be males.

 

[adrianborg]

I think you need to look at your current stock, remove inappropriate ones that do not match up with which species you want to keep and then go from there...

• The (good sized group of) Leopard and Zebra Danios will love the 240l for life, presuming this is a 4-foot tank with lots of upper water current. However, they are temperate water fish, that do far better at 18-20C for most of the year with a "summer season" approaching 24C for a few months.
• The Clown Loaches will need at least 25C; lots of water current; need a bigger group to form a complex hierachy ("VickiandKev" had 30+ in a 8x4x4); will need a much bigger tank long term; prone to ich if the water quality is not good enough.
• The Harlequin Rasboras will be happy in a 240l for life, but they are not fans of strong water current. Their minimum temperature needs are slightly higher (21C) than the danios too, so not a good choice to mix.
• The 5 BN catfish will love water current, but need a minimum temperature of 21C. As "Wills" said, as these grow up they will produce an awful lot of waste, I recently visited a breeder where 20-odd ~2cm fry were demolishing half a 3" courgette in under 24 hours. Could potentially be problems long term if more than a couple turn out to be males.

Wow, thanks a lot for the advice. It is a 4-footer with a strongish current near the surface. I put the danios in first after cycling the tank for a few weeks - wanted something easy to start with to help cycle the tank for a few weeks before adding anything else - especially as this was my first aquarium. Water is at 24-25C, all fish seem to be happy. I know the clown loaches will outgrow the tank eventually and I'll have to give them away one day but I had an infestation of ramshorm snails so I thought I might as well add something that could appreciate these guests! I've noticed the BNs poop a lot but I give the gravel a good syphon every week plus a 20-40 litre water change. They've done a great job keeping the algae under control and eliminating slime mould from the bogwood when even boiling for 3 hours failed - they're also fun to watch and not as timid as I thought they would be.
Longer term, are you saying the danios won't thrive at 25C? Would you eventually switch them out?

 

[N0body Of The Goat]

Keeping Leopard/Zebra Danios permanently at 25C is going to keep their metabolism in permanent hyperdrive; they will be even more active than the average very active danio; they will need more fuel (food) to meet this lifestyle (just like exposing aquatic plants to high intensity T5 lighting to daily long photo periods); they will therefore produce more waste (ammonia); which will produce higher concentrations of nitrate if the bacterial colony is keeping up; which means large weekly water changes (at least 50%); but ultimately they will have a reduced lifespan. Other common hobby fish are often destined to similar fates, such as Redline Torpedo Barbs; Peppered Corydoras; Rosy Barbs; Chineese Barbs; Bearded Corydoras; Blind Cave Tetra; Odessa Barbs; Paradise Fish; many Central American livebearers etc.

If you plan to raise the Clown Loaches in this 240l before rehoming them or upgrading them to a 6x2x2, then you should consider rehoming these danios sooner rather than later and probably the Harlequin Rasboras (who will be unlikely to appreciate the 8-12x water turnover needed by powerheads and filters to keep the Clown Loaches in a suitable setup). After all, there are plenty of other schooling fish you could replace them with who would love 25C water with a strong current.

As for your 20-40l weekly water change, you need to be doing an awful lot more than that, something more in the 120-200l ballpark would be more appropriate. Growing fish have their growth rate reduced by chemicals they naturally release into the water, not to mention the extra food they need will result in a buildup of nitrates which eventually do reach toxic levels even for hardy fish. I currently do ~50% water changes twice weekly on my 620T containing ~35 Lionhead Cichlid fry and my 48x12x15 containing some Synodontis (decora; nigriventris; flavitaeniata) and Limones Splitfin (livebearer) youngsters, upping the water change regime has had a very noticeable growth rate increase.