The Fluval Flex series has become one of the most popular aquarium ranges for beginners and aquascaping enthusiasts alike. With sizes available in 34 litres (9 US gallons) and 57 litres (15 US gallons), the Flex combines modern design, built-in multi-stage filtration, and powerful LED lighting that supports plant growth.
One of the most exciting parts of setting up a new tank is deciding which fish and plants to keep. To help you get started, here’s a guide to the best stocking options and aquatic plants that thrive in Fluval Flex aquariums.
Choosing the Right Fish for Your Fluval Flex
Because of their size, the Fluval Flex models are best suited for small tropical community setups. Stock lightly and avoid overcrowding to ensure a healthy ecosystem.
Top Fish Choices for the 34L (9 US gal)
- Neon Tetras: Small, colourful, and peaceful schooling fish that stand out under LED lighting.
- Harlequin Rasboras: Hardy and active, perfect for small community tanks.
- Guppies: Colourful, beginner-friendly livebearers that add movement to your setup.
- Betta Fish (Single Male): A striking centrepiece fish; keep alone or with shrimp/snails.
- Cherry Shrimp and Nerite Snails: Excellent clean-up crew for algae and detritus.
Top Fish Choices for the 57L (15 US gal)
- Cardinal Tetras: Larger and more vibrant than neons, ideal for bigger shoals.
- Corydoras Catfish: Peaceful bottom-dwellers that help keep the substrate clean.
- Dwarf Gouramis: A colourful centrepiece fish for a planted community tank.
- Endler’s Livebearers: Small, active, and very colourful.
- Otocinclus Catfish: Great algae eaters for well-established, planted setups.
Pro Tip: Always research compatibility before mixing species. Introduce fish gradually to allow the tank’s beneficial bacteria to adjust to increased bioload.
Best Plants for Fluval Flex Aquariums
The Fluval Flex comes with RGB + White LEDs (6500–7000 K), which provide the perfect spectrum for growing many popular aquatic plants. With the right aquascaping approach, you can create a lush, natural environment that complements your fish.
Beginner-Friendly Plants
- Anubias: Slow-growing, resilient, and attaches easily to rocks or driftwood.
- Cryptocoryne: Great mid-ground plants that adapt well to Flex conditions.
- Java Moss: Perfect for shrimp tanks and provides excellent hiding spots.
Intermediate to Advanced Plants
- Dwarf Hairgrass (Eleocharis sp.): A carpeting plant that creates a lush, green foreground.
- Monte Carlo (Micranthemum tweediei): Popular for creating vibrant carpet effects.
- Rotala Rotundifolia: Provides colourful red tones under strong lighting.
- Ludwigia Repens: A fast-growing stem plant with striking red and green leaves.
Floating Plants
- Salvinia or Amazon Frogbit: Great for shading, reducing algae, and giving fish shelter.
Pro Tip: Use a nutrient-rich substrate or root tabs for heavy root feeders like crypts, and consider liquid fertilizers or CO₂ injection for demanding plants.
Building a Balanced Ecosystem
When pairing fish and plants in the Fluval Flex, aim for a balanced aquascape. Active shoaling fish like tetras look stunning against a planted background, while bottom dwellers like corydoras enjoy shaded areas and hiding spots. Live plants also help regulate water quality, reduce algae growth, and create a more natural environment for your livestock.
Final Thoughts
The Fluval Flex aquariums are versatile enough to house a wide range of fish and plants. Whether you prefer the smaller 34L or the larger 57L, both models allow you to design a thriving aquatic world full of life and colour. By choosing the right stocking combinations and selecting plants suited to the Flex’s lighting and filtration system, you can create a stunning display that’s easy to maintain and enjoyable to watch.
