Starting a new semi-aggressive tank

[Oranbega]

My girlfriend and I have been preparing a 75 gallon tank over the last week for freshwater fish. Ive been closely monitoring the water chemistry every few days before we actually add at fish. We had a bit of an ammonia problem initially as it used to be a turtle tank (I assumed remnants of solid turtle waste would do that).

I've been treating it and everything is now within normal levels. The water is still hard at about 150-200 GH but I'm not sure what I can do about that on this scale. We live in an apartment so a water softener isn't an option, but I'm wondering if I need to soften it much at all. I have a feeling I'm okay to start but might need to find a solution later given the fish we'd like...

To start we're looking at some hearty fish (Namely some rosy barbs and pictus catfish) but ultimately we'd love to have an iridescent shark (catfish) in there. I am aware of how large they get and how fragile they are which is why we want to get the water chemistry good long before we introduce one.

The tank is staying a nice toasty 78-80 F or so. Anyone able to weigh in on how hard water can be and still sustain an iridescent shark?

 

[librarygirl]

Not sure an iridescent is the best choice for an aquarium: Iridescent shark - Wikipedia, the free encyclopedia

There are other sharks that would be more suitable like red tailed sharks or bala shark or rainbow shark.

Also are you feeding the tank ammonia at all? Letting the tank run doesn't cycle it. Here's some links for you:
http://www.aquariumadvice.com/forum...guide-and-faq-to-fishless-cycling-148283.html
Guide to Starting a Freshwater Aquarium - Aquarium Advice

 

[BozziniINC]

Balas recquire big aquariums do an oscar if u want a lively fish. And with that u could also add a sengal bichir which are amazing fish that are like eels.

 

[Oranbega]

It's interesting the more I read about these iris they really are meant for a vastly larger habitat. Thanks for the heads up. It's kind of sad how many of them are in 75 g aquariums on YouTube.

The red tailed black shark looks like it would do well in 75 gallons. My girlfriend doesn't want oscars--their appetite has fostered a fear haha.

The bichir is definitely an option too.

 

[Oranbega]

Not sure an iridescent is the best choice for an aquarium: Iridescent shark - Wikipedia, the free encyclopedia

There are other sharks that would be more suitable like red tailed sharks or bala shark or rainbow shark.

Also are you feeding the tank ammonia at all? Letting the tank run doesn't cycle it. Here's some links for you:
http://www.aquariumadvice.com/forums/f15/the-almost-complete-guide-and-faq-to-fishless-cycling-148283.html
Guide to Starting a Freshwater Aquarium - Aquarium Advice

I've been doing what I thought was fishless cycling. This post will vastly help this process lol. Thank you!

I had to reduce the ammonia which was at a dangerous level because the tank used to house turtles. I used a moss that eats ammonia and excretes oxygen and an ammonia reducer chemical for aquariums.