Fish Oil in Australia: EPA vs DHA, rTG vs Ethyl Ester & How to Read the Label (2026 Guide)
The number on the front of the bottle is usually not what you think
Fish oil is one of the most confusing supplement categories to shop, and almost all of the confusion comes from one thing: the big number on the front is rarely the number that matters.
A bottle that says 1000mg might be telling you the weight of the oil in each softgel. A bottle that says 1280mg might be telling you total omega-3s. Neither tells you how much EPA and DHA you are actually getting, which is the figure everything else hangs on.
This guide covers how to read the panel properly.
Fish oil, omega-3, EPA and DHA — these are four different things
Fish oil
The whole oil pressed from the fish. A 1000mg softgel contains 1000mg of oil, most of which is not omega-3.
Total omega-3s
The portion of that oil that is omega-3 fatty acids. In a standard fish oil this is often around 30%, so a 1000mg softgel might contain 300mg of omega-3s.
EPA (eicosapentaenoic acid)
A long-chain omega-3 found in oily fish.
DHA (docosahexaenoic acid)
The other major long-chain omega-3 found in oily fish and marine algae.
EPA and DHA together are usually less than total omega-3s, because the total includes other omega-3 fatty acids as well. A label reading "1280mg total omega-3s, 650mg EPA, 450mg DHA" means 1100mg EPA+DHA and 180mg of other omega-3s. Some front labels round that up and print 1280mg next to "EPA & DHA." Check the panel.
Triglyceride, re-esterified triglyceride, ethyl ester
This is the other figure worth understanding, and it rarely appears on the front.
Natural triglyceride (TG)
The form omega-3s take in the fish itself. Unprocessed fish oil is in this form, but it cannot be concentrated very far without processing.
Ethyl ester (EE)
Produced when fish oil is concentrated. The fatty acids are separated from their glycerol backbone and attached to ethanol instead. This allows much higher EPA and DHA concentrations, and it is cheaper to produce. Most high-strength fish oils on the market are ethyl esters, and many do not say so.
Re-esterified triglyceride (rTG)
An extra manufacturing step that converts the ethyl ester back into triglyceride form after concentration. It costs more to produce, which is why products using it tend to state it prominently.
How to tell which you have: if the label says "triglyceride form" or "rTG," it is stating it because it is a selling point. If the label says nothing about form, it is most likely an ethyl ester.
Purity: molecular distillation and heavy metals
Fish accumulate environmental contaminants — mercury, dioxins, PCBs — and larger, longer-lived fish accumulate more.
Two things on a label address this:
Fish species. Anchovies, sardines and mackerel are small, short-lived and low in the food chain, which is why most quality fish oils use them. Oils from larger species carry more risk.
Molecular distillation. A purification process that separates contaminants from the oil by molecular weight. Most reputable manufacturers use it, and most say so.
If a product claims to be free of PCBs, dioxins or heavy metals, that claim should be backed by a certificate of analysis. It is reasonable to ask a retailer for one.
Why there is vitamin E in your fish oil
Not a bonus ingredient — a necessary one. Omega-3 fatty acids oxidise readily, and oxidised fish oil tastes and smells rancid. Vitamin E (tocopherol) is added as an antioxidant to protect the oil in the capsule.
Rosemary extract performs the same job in some formulations.
The freshness test
Bite one. A fresh fish oil capsule tastes mildly of fish or of nothing much. A rancid one tastes sharply unpleasant and is immediately obvious. If a bottle fails that test, it has oxidised — regardless of the expiry date printed on it.
Store fish oil in a cool, dark place. Heat and light accelerate oxidation.
Softgels, liquid and the vegan option
| Softgels | Liquid oil | Algal oil | |
|---|---|---|---|
| Taste | None | Noticeable | Noticeable |
| EPA & DHA per dose | Moderate | Highest | Usually DHA-dominant |
| Suits vegans | No (gelatin) | No | Yes |
| Travel | Easy | Harder | Varies |
Softgel shells are made from gelatin — animal-derived. Fish oil is not vegetarian regardless, but it is worth knowing if you are checking the capsule itself.
Algal oil is the vegan alternative, derived from marine algae — which is where fish get their omega-3s in the first place. It tends to be DHA-dominant with less EPA, and costs more per milligram.
Flaxseed, chia and walnut oils provide ALA (alpha-linolenic acid), a different omega-3. The body converts ALA to EPA and DHA only at low rates, so a plant oil is not a like-for-like substitute for fish or algal oil. If a product lists omega-3 from chia or flax, that is ALA, not EPA and DHA.
Allergen declaration
Fish is a mandatory declared allergen in Australia under FSANZ Standard 1.2.3. Any fish oil product should carry a clear "contains fish" statement.
If a label does not declare it, that is a labelling defect, not a sign the product is fish-free.
Six things to check before you buy
- EPA and DHA in milligrams, from the supplement facts panel — not the front of the bottle
- Serving size — one softgel or two? This changes the per-day cost completely
- Form — triglyceride or rTG will be stated; silence usually means ethyl ester
- Fish species — small fish such as anchovy and sardine
- Molecular distillation or a stated purity process
- "Contains fish" allergen declaration
How to take it
Follow the directions on the product label. Fish oil is fat-soluble and is commonly taken with a meal containing fat.
Speak to your doctor or pharmacist before use if you take any medication — particularly blood-thinning medication — or if you are scheduled for surgery, pregnant or breastfeeding.
Browse our softgels and capsules →
Always read the label and follow the directions for use. This article is general information about supplement labels and formats, not health advice. Supplements should not replace a varied, balanced diet. If symptoms persist, talk to your health professional.