Poorman's Monster Fish Tank

[johnnymax]

Here is my long time coming project. I want to set up a tank I can afford to set up, stock, feed and maintain. I have been contemplating this tank for over a year and I am finally determined to do it. I just want a tank that I can enjoy and watch and with fish that will interact with me, so I will go with ordinary Oscars. I will add a Pleco, just because I think they look like a dragon in style.



Here is my build plan. Please feel free to hammer me, as I am often persuaded to change course by wise counsel.

Day 1 – Preparation Work – Initial Setup

1. Clean & Sanitize
   • Rinse the aquarium, canister filter, and all media using clean tap water.
   • Use vinegar to clean tough spots.
   • Clean the outside back glass and spray 4–6 light coats of Plasti Dip.
2. Install Under Gravel Filter
   • Lay out the under gravel plates evenly.
   • Attach two 250 GPH powerheads to the uplift tube.
3. Add Substrate
   • Add 2–3 inches of rinsed small pea gravel to cover the plates completely.
   • Add Osmocote root fertilizer caps in back corners to feed Jungle Val plant initially.
4. Place Hardscape
   • Arrange large limestone and river rocks.
   • Build a sturdy central formation in the center as an island encouraging fish to swim around it and ensure good water circulation.
5. Connect Canister Filter
   • Fill with clean media (sponge, bio-rings, etc.).
   • Connect and secure hoses.
6. Fill with Chlorinated Tap Water
   • Fill slowly to avoid disturbing layout.
   • Do not dechlorinate yet.
   • Cover the tank top tightly with plastic wrap to trap chlorine.
7. Circulate Water for 48 Hours
   • Run the canister filter and powerhead continuously.
   • This acts as a mild sterilization phase using chlorine.

Day 3 – Water Conditioning

1. Uncover and Vent
   • Remove plastic wrap. Let chlorine off-gas for.
2. Add Dechlorinator
   • Example: Seachem Prime — use 5 mL per 50 gallons (use ~7.5 mL for 75 gallons).
3. Add Beneficial Bacteria

• Add a full bottle of API Quick Start.
• Pour directly into the tank and filter intake.

1. Add Ammonia

• Use 10% pure ammonia. Add enough to reach 2 ppm.
• That’s about 3 teaspoons for 75 gallons (confirm with a test kit).

Day 4 – Planting and Fertilization

1. Prepare Hydrogen Peroxide Dip (To Kill Snails/Algae)

• In a clean container, mix 1 part 3% hydrogen peroxide to 4 parts water.
• Submerge plants for 5 minutes.
• Gently rinse with clean tap water.
• Let plants drip dry for a minute while attaching.

1. Attach Anubias to Rocks

• Drill a small hole in the rock, insert a hooked stainless wire, and secure with gel super glue.
• Wrap the wire loosely around the plant rhizome.

1. Place Plants and Add Fertilizer

• Position the Anubias-attached rocks.
• Add liquid fertilizer such as Seachem Flourish — 5 mL per 60 gallons (use ~6.25 mL).
• Start light cycle using a timer:
  • 12:00–9:00 PM

Days 5–13 – Cycling Period

1. Monitor Water Chemistry

• Test for ammonia, nitrite, and nitrate daily.
• Ammonia should drop and nitrite will spike before converting to nitrate.
• No water changes unless ammonia exceeds 4 ppm.

1. Optional: Algae Control

• Add API Algaefix only if algae blooms occur.
• Avoid if Anubias show signs of stress or melting.

Day 14 – Fish Introduction

1. Prepare Salt Dip

• In a separate container, dissolve 1 tablespoon of aquarium salt per gallon of dechlorinated water.
• Gently place each fish in the salt bath for 30–60 seconds.
• Remove with net and transfer directly into the tank.
• Observe for aggression and stress, especially during first 48 hours.

I have been planning and tweaking my do list way to long. Time to just do it...

 

[jjohnwm]

Nothing like a detailed plan to set up a new tank!

I will not make a couple of comments that tend to start discussions/debates/arguments...comments regarding the tank size vs. stocking plan. However, someone will surely opine that a 75gallon tank is not really even adequate for a single Oscar in the long term, let alone multiple Oscars plus a pleco, and I will immediately agree with them.

Someone else will suggest that Oscars and UG filters just won't work together; I'll agree with them too. Oscars are so fascinated by UG filters that they invariably dig them up to get a better look, thus making them ineffective. They'll even dig up the bottom of tanks without UG filters, just to check and make sure. This also disrupts most plants rooted in the substrate; any stones big and heavy enough to protect the plants are going to take up a large percentage of your very limited swimming room.

You can perhaps make it work...perhaps... by covering the UG filter with a layer of gravel, then carefully laying down a single large sheet of plastic window screen, then covering that with more gravel. The problem then is twofold; first, the Oscars will still dig up the top layer of gravel, exposing the screen which looks like hell. Second this ends up being a very thick layer of gravel overall, taking up even more room in that very small Oscar tank.

I would also consider the salt dip and the "trapped chlorine" thing to be pretty much a waste of time, effort, salt and Saran Wrap, though likely harmless.

How about some suggestions from some of our Oscar keepers; FINWIN Jexnell DawnMichele leap to mind but there are many others.

Your planted tank is a delight! I saw your other post in which you described its maintenance schedule. Please don't think that Oscar(s) in a 75-gallon tank will allow that same sort of relaxed luxury; this tank, if you proceed as you propose, will be a horse of an entirely different colour...time and labour intensive, lots (and I mean lots!) of water changes...180 degrees opposite to your current tank.

 

[DawnMichele]

Hello. Beautiful tank but NOT for Oscars. They LOVE to rearrange their tank. I had rocks in the tank at one time. When he banged them up against the glass. No more rocks. I put a couple of plastic plants in the tank he could play with. Unfortunately they would dig up your plants and ug filter. It's also too small for them. I kept my Big Boy in a 125. He made that look small.

 

[tlindsey]

Oscars are so fascinated by UG filters that they invariably dig them up to get a better look, thus making them ineffective. They'll even dig up the bottom of tanks without UG filters, just to check and make sure.

Very true .

 

[johnnymax]

Tank cleaned and painted.

 

[johnnymax]

Just a quick reply. I am glad I posted my plans before committing. I am now planning to make it as Oscar friendly as possible. I have thoughts, but input my help me get it right a little quicker. Thoughts?

 

[Jexnell]

My best suggestion.
Ditch the UG filter, get a pair of AC110's
Ditch the Oscar pleco combo, two 12in plus fish in a 75 is a disaster in the makings.
Now as far as fish go. What are the peramaters of the water you will be using for your water changes? High PH hard water, or low PH soft water. This answer will dictate the fish you will be able to keep. As keeping Hard water high PH fish in softwater leads to hole in the head disease. And vise versa soft water fish in hard water leads to bloating and death.

 

[johnnymax]

Appreciating the feedback.
I’ve decided to ditch the undergravel filter based on earlier suggestions. It was originally going to run alongside my Polar Aurora 3-Stage Canister Filter with UV Light (370 GPH). For now, I’ll use the canister filter alone. If needed later, I will add my Marineland Penguin HOB Filter (350 GPH), which is currently unused but ready.

As for stocking, I’ve also decided to ditch the pleco due to its bio-load. My main goal is to keep Oscars, so I’m focused on making the most of the tank and equipment I already have. I’ve kept and bred cichlids before, so I’m comfortable managing water chemistry. To easily raise the pH, I’ll use crushed oyster shell as the substrate. A 50 lb. sack runs about $17.50 at Tractor Supply. It takes a little extra effort to rinse, but after a day or two, the water clears up beautifully. I used it in reef tanks before as well. It looks good too.

Revised Plan:

• 75-gallon long tank with Oscars only
• Crushed oyster shell substrate
• Polar Aurora 370 GPH Canister Filter with UV and a pre-filter to catch uneaten food
• Optional: Marineland Penguin HOB filter for extra filtration if needed later
• No plants or rocks , just Oscar-safe toys for enrichment

I’ve got a few creative, awesome, fun ideas for Oscar toys that should keep them active and engaged. And be fun to watch them push around.
Now, off to Tractor Supply.

 

[Jexnell]

Oscar's won't need the raised PH. They naturally come from low PH soft waters of the Amazon. Shoot for mid 6 or lower and hardness of 50 or less. This is why I gave my beautiful Osace Toni away to a fellow MFKer. My water change water was PH of 7.8 and hardness of 350. The city drew it water from limestone aquifers.
So go the other way, you need soft low PH water.

 

[johnnymax]

well... I am glad i did not go buy the oyster shell yet. I did a quick check here first.

To know so much, I know so little.....
Let me check my PH