New Aquarium, New Problems

I don't know how many of you know about keeping fish as a hobby or tank maintenance and all that stuff. I've been a member of www.myaquariumclub.com for while and have learned so many new things about how best to keep different types of fish. Awesome, right?

For a few months, I've been wanting to acquire a hospital tank. A hospital tank is basically what it sounds like. You keep an empty tank cycled and healthy and whenever a fish gets sick and needs treatment, but you don't want to treat your entire tank, you move the sick fish to the hospital tank and treat it separately. This keeps diseases contained and lessens the risk of treating the entire tank and other fish being harmed by medicine/salt/what-have-you. 

My cousin has a 10 gallon tank which would serve my purposes well. I only have a 29 gallon and a 10 gallon tank with fish in it, so 10 gallons for a hospital tank is what I needed. I messaged her and she said I could definitely have her tank and her fish. 

She has 2 fancy goldfish. One is a bubble-eyed goldfish and the other is black. I assume the black one is a goldfish as well, since she didn't really say. The thing about goldfish is they're messy and misunderstood. The fact that they're messy alone is enough to warrant them a larger tank, but they can grow to much larger lengths than most people imagine, if kept in a healthy environment. 

A 10 gallon tank doesn't suit 2 goldfish. 

So, being that I am going to take her fish and tank (I can't live with myself knowing that she isn't cleaning the tank or caring for the fish), I went on PetSmart's website and found that they're still having a tank sale in store. There's a 40 gallon tank/hood/light combo that is a little over $100. I found a good filter for about $40, and I already have an air pump and a bubble wand. I'd just need decoration and some substrate (a 20lb bag of sand is about $26, decoration can come later). So we're looking at me spending about $200 on 2 fish for their tank to be closer to an ideal level. I have a dresser that is long enough to put the tank on, and it would be downstairs with all my other tanks. 

The problem is that I'm not entirely aware of my tax refund. Plus, my fiance isn't fond of me keeping 2 tanks, let alone 4. Add that to me having to spend over $200 to keep some random fish happy and I don't think he's going to be happy about it at all. 

I texted him the details of everything I found, told him I have the space for it all and that I would never ask him to let me get another tank again. I mean, 40 gallons is pretty huge to me. My 29 gallon is huge to me... I hope he responds well... And I hope that he let's me do it. I mean, it's selfish of me to say, but I promise to him and everyone else that this will be the last tank I buy. 4 tanks is a lot of maintenance and I think about as much as I'm capable of handling.