Sad news for my first ever aquarium, some unexpected good news, and a stocking question

[mbwells]

Hello friends,

The bad news: I have been distracted from the forum again.  I have no idea why, but the spotted dwarf danios I bought started falling apart in my water.  I had 3 deaths back to back, and in each case, the fish would appear to be completely healthy until they started swimming like they were suffering from ammonia burn (my ammonia and nitrite levels are always 0 ppm and my nitrates between 10 and 25 ppm), and then die rapidly a few hours.  Before this, I was playing a game of whack-a-mole, medicating for all manner of different infections.  In the midst of all of this, I had a thriving community of 16 Vietnamese white cloud minnows (Tanichthys micagemmae).  I can only guess that my water chemistry (I'm using fresh UNS Controsoil as a substrate, so my pH is always around 6.5 to 6.6 without exception) was not agreeable for them.

The good news: After a bit of searching, the local fish store in an area I've just moved to helped me re-home these special little danios.  It was so hard giving them away.  I had fallen in love with their gorgeous appearance.  Since I already had a school of Vietnamese white clouds who liked it a bit cool, I decided to get 15 gold white cloud mountain minnows (Tanichthys albonubes).  This has turned out to be a terrific decision.  My danios were always rather shy, and they seemed to have made the Vietnamese white clouds more subdued.  The gold white clouds have added so much activity and *life* to my tank, and they're already spawning every day.  The males of both species display at one another constantly.  It's never a dull moment!

Question about stocking: I'm keeping about 30 Tanichthys fish in my 40 gallon breeder at 74 degrees.  I have an Aquarium Co-Op 40 gallon sponge filter to the left, a Seachem Tidal 55 HOB in the middle (supplemented with the Aquarium Co-Op in-take sponge filter, fine filter floss, and ceramic rings), and a Ziss bio-bubble filter to the right.  My apartment only allows me one tank right now (I'm working on that!!) so I decided to keep the sponge filter in there so it would be ready to seed my next tank with beneficial bacteria. 

Here's my problem: I'm still a danio guy!!  I'd love to find a way to add some to my tank, if there is sufficient space and filtration capacity to accommodate them in my tank.  I'd love to get opinions from more experienced fish keepers.  Should I leave it at 30 white cloud minnows, or could I accommodate 10-12 pearl danios (Danio albolineatus) or zebra danios?  My white clouds don't spend much time in the top of the aquarium.  I would be open to adding some nano fish, but I'm pretty sure my water chemistry would kill CPDs, and it definitely would kill emerald dwarf rasboras.  Any thoughts would be welcome!! 

PS- included a picture of my tank!  Apologies for the glare. 

[nabokovfan87]

Congratulations on the awesome tank, very nice!

I will answer your question with a question.... Have you considered some Corys?

Everything you're mentioning, the white clouds, the danios, (and a lot of varieties of Corys too) are cooler temperature species. So they should actually be doing well together. Once the plants grow a bit their behavior will level out.

A few options you have is to consider a different source for the fish (maybe aquahuna works for you) to try to find some danios that work a bit better in your water.

[mbwells]

@nabokovfan87, thank you for your suggestion!  However, I would strongly prefer to maintain the Asian theme of my tank, so I'd be more likely to get some neocardinia shrimp or dwarf anchor cats over corydoras.  I hope one day to do a large South American tank however with a large school each of tetras, corydoras, and hatchetfish!

[nabokovfan87]

On 3/26/2022 at 12:12 PM, mbwells said:

However, I would strongly prefer to maintain the Asian theme of my tank, so I'd be more likely to get some neocardinia shrimp or dwarf anchor cats over corydoras. 

Totally makes sense. The stockings you had should be ok and work well (with the danios) and everything you have currently.

[Cinnebuns]

I just wanna say you should move here. This apartment building's tank rules blow my mind. Literally no limits to size or amount of tanks. They have however warned people to have them sitting on more solid surfaces before. Not to me cause I'm already paranoid about that lol. 

[sumplkrum]

Looks like you've got way more filtration than you need. If there's swimming space you should be more than fine with danios.

I have a similar-sized tank with a dozen danios, a much higher stocking level of other fish, and only one large sponge filter.