---
product_id: 53908540
title: "Blue Shark (Formerly Colony Marine Rapid Cycle 25 gal Tank Cycle 8 oz"
brand: "atm"
price: "€ 52.75"
currency: EUR
in_stock: true
reviews_count: 13
category: "Atm"
url: https://www.desertcart.hr/products/53908540-blue-shark-formerly-colony-marine-rapid-cycle-25-gal-tank
store_origin: HR
region: Croatia
---

# Add fish same day, instant bio-filtration Authentic nitrifying bacteria strains Cycles aquarium in days, not weeks Blue Shark (Formerly Colony Marine Rapid Cycle 25 gal Tank Cycle 8 oz

**Brand:** atm
**Price:** € 52.75
**Availability:** ✅ In Stock

## Summary

> 🐟 Cycle fast, fish faster—join the aquarium elite!

## Quick Answers

- **What is this?** Blue Shark (Formerly Colony Marine Rapid Cycle 25 gal Tank Cycle 8 oz by atm
- **How much does it cost?** € 52.75 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/53908540-blue-shark-formerly-colony-marine-rapid-cycle-25-gal-tank)

## Best For

- atm enthusiasts

## Why This Product

- Trusted atm brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Trusted by Pros:** Used and approved by commercial aquariums worldwide.
- • **Marine-Grade Strains:** Nitrococcus & Nitrosococcus for superior marine environment performance.
- • **Instant Fish Addition:** No more waiting weeks—add fish the same day you cycle.
- • **Rapid Aquarium Cycling:** Transform your tank in days, skipping the usual wait.
- • **True Nitrifying Bacteria:** Only the right species for effective ammonia and nitrite control.

## Overview

ATM Blue Shark delivers authentic nitrifying bacteria strains that rapidly cycle marine and freshwater aquariums in days, enabling immediate fish introduction. Trusted by public aquariums globally, this liquid treatment ensures efficient ammonia and nitrite breakdown with proven commercial-grade performance.

## Description

Product Description Colony True Nitrifying bacteria is the industry standard in aquarium cycling, used by public aquariums around the world such as Sea Life Sanctuaries to cycle aquatic systems in days instead of weeks. Directions Add product to aquarium, add fish same day, wait for bacteria to establish bio-filtration

Review: as described - as described real quick delivery and good product
Review: Good - Good product

## Features

- CYCLES: The one that works, effectively imports actual true nitrifying bacteria
- AUTHENTIC: Other products don't contain the right species of bacteria, Colony Freshwater does!
- STRAINS: Nitrococcus & Nitrosococcus for primary ammonia and nitrite consumption in the marine environment
- INSTANT: Add fish same day, not weeks later
- PROVEN: Used and approved by commercial aquariums

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00YW5SQPA |
| Best Sellers Rank | 33,229 in Pet Supplies ( See Top 100 in Pet Supplies ) 347 in Aquarium Water Treatments |
| Brand | ATM |
| Brand Name | ATM |
| Country Of Origin | United Kingdom |
| Customer Reviews | 4.6 out of 5 stars 293 Reviews |
| Global Trade Identification Number | 00870317004127 |
| Included Components | Nitrifying bacteria |
| Item Form | Liquid |
| Item Type Name | Aquarium rapid cycle |
| Item Weight | 227 g |
| Item form | Liquid |
| Item weight | 227 g |
| Liquid Volume | 8 Fluid Ounces |
| Liquid volume | 8 Fluid Ounces |
| Manufacturer | Blue Shark LLC |
| Manufacturer Part Number | 870317004127 |
| Model Number | 870317004127 |
| Target Species | Fish |
| UPC | 870317004127 |
| Unit Count | 1 count |
| Unit count | 1 count |

## Images

![Blue Shark (Formerly Colony Marine Rapid Cycle 25 gal Tank Cycle 8 oz - Image 1](https://m.media-amazon.com/images/I/71H675rbOrL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: Can this b used when doing water charges**
A: yes but you have to keep skimmers off for 4 days when using it

**Q: Can this  more then once**
A: Yes No need to bacteria grows

**Q: My LFS just told me to add a bottle and wait for the ammonia to drop without having fish in cycle, but states adding fish??**
A: Yes add whole bottle wait an hour add couple of small fish but don't over feed them

**Q: Is this for saltwater tank**
A: Yes, I used this when I set up my marine tank and it worked great. I was able to add fish and livestock a lot quicker.

## Customer Reviews

### ⭐⭐⭐⭐⭐ as described
*by H***E on 20 May 2025*

as described real quick delivery and good product

### ⭐⭐⭐⭐ Good
*by W***Y on 27 February 2020*

Good product

### ⭐⭐⭐⭐⭐ Yes it works
*by N***K on 18 November 2024*

After weeks of water quality issues, added the colony and then 24 hours later boom. Worked better than expected. Will grab another one to have on hand . Highly recommend Ps don't use the bio balls it will stall your cycle.

## Frequently Bought Together

- ATM Blue Shark (Formerly Colony Marine Rapid Cycle 25 gal Tank Cycle 8 oz
- iQuatics Ocean Reef Pro Marine Saltwater Coral Premium Aquarium Salt - 10KG - Refill

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**Shop now:** [https://www.desertcart.hr/products/53908540-blue-shark-formerly-colony-marine-rapid-cycle-25-gal-tank](https://www.desertcart.hr/products/53908540-blue-shark-formerly-colony-marine-rapid-cycle-25-gal-tank)

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*Product available on Desertcart Croatia*
*Store origin: HR*
*Last updated: 2026-10-17*