Can anyone suggest what wrong?

[Retired Viking]

All your tetras are shoaling fish (need 6 or more ) and so are the cory and most need more room to swim then your current tank which is way over crowded. You have 42 fish in a 27 gallon tank.

 

[JuiceBox52]

Bent spines in fish are usually caused by inbreeding and genetic issues.

Yep, but if this is a new development (it didnt have it before) it could be something to do with it. TB can cause bent spines as well as one or 2 others

 

[PheonixKingZ]

Can you tell us what type of water do you have? Hard or soft and the GH (general hardness) you have soft water fish such as cory and tetras and hard water fish such as Platties

The OP has soft water, as his pH is around 7. Hard water is classified over 8.5.

 

[CablePixie]

Rummynose need at least 10 and requires warmer water than some of the others. Nded a longer tank.
Neons need a longer tank

The rams will likely start fighting depending on the gender

Corydoras need a larger group and sand substrate

Do you know the sex of the gourami? They may fight.

Thanks for this - I’ve got 3 cobalt dwarf gourami all female. 3 peppered corys which the guy in the shop said they’re better for gravel instead of sand. I’ve got gravel.
rams are two male and a female. One male and female have petty much paired up and the other just chills out on his own. Not had any issues but only had them a week. Do you suggest I get more fish then?

 

[JuiceBox52]

Thanks for this - I’ve got 3 cobalt dwarf gourami all female. 3 peppered corys which the guy in the shop said they’re better for gravel instead of sand. I’ve got gravel.
rams are two male and a female. One male and female have petty much paired up and the other just chills out on his own. Not had any issues but only had them a week. Do you suggest I get more fish then?

Dont get more fish, if anything rehome some

 

[JuiceBox52]

Rehome the extra male ram.
Rehomee the corydoras or get sand rehome the rummy and neons

 

[JuiceBox52]

Also rehome the platies

 

[CablePixie]

Also rehome the platies

Thanks - what would recommend then? Ideally I wanted a tank of German blue rams and electric blue rams with a few other fish

 

[JuiceBox52]

Thanks - what would recommend then? Ideally I wanted a tank of German blue rams and electric blue rams with a few other fish

In a tank this size rams will fight if you have more than 1 pair.... once you rehome all of those fish get maybe 2 more of each remaining tetra and leave it at that. Anything more will overstock

 

[CablePixie]

The OP has soft water, as his pH is around 7. Hard water is classified over 8.5.

The water in my area is moderately soft. Sometimes after a water change I’ll need to add a PH booster to get it back to 7

 

[JuiceBox52]

The water in my area is moderately soft. Sometimes after a water change I’ll need to add a PH booster to get it back to 7

Dont use ph boosters. The fluctuation of the ph is super bad for fish

 

[CablePixie]

Dont use ph boosters. The fluctuation of the ph is super bad for fish

Looks like I’ve been getting really bad advise from my fish store. Before I buy new fish I’ve told them everything about the size of the Tank and what’s in it

 

[JuiceBox52]

Looks like I’ve been getting really bad advise from my fish store. Before I buy new fish I’ve told them everything about the size of the Tank and what’s in it

Sadly fish stores rarely know what they need too. Most of us here learned that the hard way.

 

[Colin_T]

what is denetrol?

the harlequin has a genetic defect (bent spine) and it is not from TB.

if you have a cycled aquarium, just move half the filter media into the new tank for an instant cycled tank.

 

[WhistlingBadger]

Hi, Pixie. This can be a bit overwhelming, but you're being given some good advice here. Don't feel bad--most of us have been there, and we're here to help--but listen up and learn, learn, learn!

As for stocking: There's a website called AQadvisor. Check it out. Experienced aquarists can often get away with stocking more than what it says, but for beginners it's right on the money. It will warn you about common incompatibility and school size issues, too.

Right now, your tank is very overstocked, and you have some compatibility issues. If it were me, I would find new homes for the gouramis, the platies, and the harlies for starters. Then play around with aqadvisor until you get your species compatible and your stocking level well under 100%. You have a really pretty setup, and it can be saved!

Different fish have different personalities and different needs, and if you pick them purely on looks or local pet store advice, you're going to end up with some incompatible species and/or wrong conditions.

Forgive me if you mentioned this, but are you testing for ammonia? Also, what do you mean by "practically nothing" for nitrites? Any measurable amount of nitrite is toxic to fish. It sounds like you added a lot of stock to an uncycled filter, and that's part of your problem.